Diablo III News

Developer Insights for Set Dungeons

An exploration of the design in the class-specific dungeons

Diablo III Set Dungeons Portal
Set Dungeons are a big new addition to Diablo III in Patch 2.4. A recent official blog provides insight into the development of this large new feature, and some of the ideas that the designers wrestled with when bringing it to life. The overview also provides hints at tweaks that may arrive for Set Dungeons in the future.

Patch 2.4.0 (and Season 5) introduces one of Diablo III’s newest and most exciting features yet: Set Dungeons. These static realms test your skills with various class sets, each carefully tuned around specific play styles. You may have even found that they’re a little (okay, maybe a lot) more difficult than your average Rift or Bounty!

What was the design intent behind these formidable new challenges? To answer that question, we’ve prepared this behind-the-scenes look at Set Dungeons, from their origin to what you can expect in-game.

What are Set Dungeons?

Senior Game Designer Alex Sulman, lead on the Set Dungeon project, explains that the gameplay experience for Set Dungeons will be way outside the norm. “They give you a chance to measure your skill. A yardstick of sorts,” he prefaced. “In a game like Diablo, there’s always something to do, so having something that’s more measurable and ‘beatable’ is different. It’s fresh.”

Inside an early version of the Shadow's Mantle dungeon.

Why include a feature that plays so differently from the rest of the game? Some players need an end goal where they can say that they’re done. Similar to the Season Journey, Set Dungeons accomplish this by giving a definitive goal to work towards. Class sets take effort to put together, but there’s no clear “celebration” of this accomplishment. Set Dungeons are the light at the end of that journey.

As an auxiliary goal, Set Dungeons also provide a sense of competition, though not formalized in the same manner as leaderboards. Since Set Dungeons are timed, there’s always an opportunity to go back and beat your time, or share your times with your friends and compare who’s truly the greatest among you.

We intentionally avoided formalizing leaderboards for Set Dungeons for a few reasons, in part because it would have significantly delayed the development of the feature. However, it also combats behavior where, when a leaderboard fills up, players may be discouraged from participating. Allowing the competition to remain more free between friends or clan mates makes the feature more approachable. It may feel insurmountable to compete with a top player, but when all you want to do is beat your buddies, it doesn’t seem so impossible a task.

Game Jam – Where Set Dungeons Started

Every so often, a game team might need to take a step back and go off the rails – take an opportunity to stretch their imaginations and see what kinds of crazy ideas they can make work. Several months ago, the Diablo III development team did just that, working on any creative passion project they wanted before pitching it to the rest of the team. For Alex, that meant fleshing out Set Dungeons.

One of the slides from Alex's original pitch deck.

The initial pitch is pretty much what you see in game today—a finish line for sets. The first set dungeon designed was Delsere’s Magnum Opus, and the response from the team was huge. There was a definite desire for greater challenge and testing one’s limits. Aside from some basic logistical questions, the team was ready to get this concept in game.

Iteration – Dealing with Design Complications

There wasn’t much iteration on the idea. “I’d brewed on it for a long time,” Alex says, indicating the idea was well formed from the start. However, no matter how great an idea may be, there are bound to be challenges you would never anticipate.

The biggest complexity was the introduction of multiplayer. Originally, Set Dungeons were designed as an exclusively solo experience. However, the multiplayer experience is an important part of Diablo III, and it just didn’t feel right to leave it out.

Playing Diablo with your friends should always be an option, no matter your goals.

When adding a new feature, our designers not only ask the question, “how well does this play?” but “how well does this play on PC versus console?” When we looked at Set Dungeons from a console player’s perspective, we saw a situation where, in local co-op, one of you sits on the couch flipping through your phone while the other challenges themselves in a Set Dungeon. That didn’t make for a great multiplayer experience, so it was clear a resolution was needed.

“I didn’t think it would work at first, but my teammates really helped that part come together,” Alex acknowledges. Everything from how the game would handle multiple players opening different Set Dungeons simultaneously to how the UI would look upon entry was tricky, but accomplished with group effort.

Of course, this brought both internal (and, later, community) concerns. Does the inclusion of multiplayer imply that Set Dungeons are designed to be conquered in this manner? Not at all. Players will conquer each dungeon on their own terms. For some, that might be piecing the puzzle together solo, reveling in a sense of fulfillment and personal achievement. For others, it might be getting by with a little help from their friends. Ultimately, that’s a choice each player should make for themselves, in the way that best suits their gameplay style.

Strengths and Weaknesses – Different Sets, Different Stories

As with most design projects, there were bound to be pitfalls. Some class sets and their objectives proved more difficult to design while others came much more naturally, and each had their reasons.

For example, the Thorns of the Invoker set was in the middle of a full rework at the time Alex was putting together each Set Dungeon outline. Senior Technical Game Designer Wyatt Cheng, who was tasked with redesigning the Invoker set, came to the rescue. He helped Alex define objectives and ensure the dungeon would capture the heart and essence of the set’s new powers.

Tackling the Thorns of the Invoker dungeon head on!

On the other end of the spectrum, the Barbarian Set Dungeons came naturally. Wrath of the Wastes was considered one of the best examples, and not because it’s touted as one of the more difficult. Its objectives really get at the heart of what the set is all about, which was the goal for every set. With objectives that encourage you to consider aspects like crowd management and utilizing Whirlwind to avoid taking damage as much as dealing it, it encourages a unique experience and highlights playing the game differently. That approach to objectives would become the expectation for other dungeons.

While not all the objectives came out perfectly, we want to avoid making too many changes. For example, there are a few objectives that may be too easily trivialized in multiplayer that we would like to address. We do, however, want to limit which aspects of the game we tune after release. For game elements that have a sense of achievement, we try to avoid revisions that could make players feel as though their accomplishments have been lessened.

Getting in Tune – The PTR Process

During the PTR, Alex was poring through player feedback every day. “I was mostly looking for tuning, but I paid a lot of attention to general feedback to what people liked and didn’t like as well,” he mentions, pleased with the overall reception. “The general response was exactly what I’d hoped for. It showed that the content is compelling enough to pursue and a great challenge.”

Some contributors, like Quin69 and Deadset, did thorough testing and shared their results.

Bugs were certainly another high priority. Set Dungeons were a large feature that came in hot, and the faster and larger a feature is, the more bugs it’s going to have. The PTR was invaluable in this regard—we can’t thank you enough for your participation and incredible feedback!

Final Word – Good Luck!

We hope that Set Dungeons provide a refreshing new challenge in Diablo III. They may not be for everyone, and that’s okay. Divisive content can be good for the long-term health of any game, ensuring that there really is something for everyone. Set Dungeons are meant to be tough and deviate from the traditional slay-and-loot gameplay. Are they too tough? Perhaps for some, but you’re not alone in the struggle! Even our designers feel the pressure.

“The irony is that there are several that I can’t master on live, so maybe I’m not the best to give advice!” laughs Alex. However, he does have a few tips. “The number one tip is to check your corners. Don’t blast through everything expecting to win. There’s a certain playstyle that works in each, so pay close attention to them.” Attention to detail is important, especially if you’re looking to master each set.

Finally, if you’ve conquered every Set Dungeon, don’t forget to congratulate yourself! That’s no small feat. “If you see someone running around with those beautiful green wings, bow down at their feet! They have mad skills . . . no matter which way they chose to tackle the challenge.”

Season Rebirth Mail Expiring Soon

If you used Season Rebirth, be sure to clear out the in-game mailbox

Diablo III - Seasonal Rebirth
Season 5 has been active for the better part of a month, which means that the time is running out to clear mailboxes of any items sent via Season Rebirth. The Season Rebirth feature that was added in Patch 2.4 is useful for players who wish to reuse an older hero in a new Season. An official reminder explains the process, and how to find any items that have been automatically mailed to your account.

If you jumped into Season 5 using Patch 2.4.0’s new Season Rebirth feature, it’s possible that your items may be on their way out the door! As we rapidly approach thirty days into the latest season, we wanted to remind everyone how to check on your in-game mail and recover your hard-earned loot.

What is Season Rebirth?

Season Rebirth, introduced in Patch 2.4.0, allows you to take any non-Seasonal character you have and instantly transform them into a Seasonal character.

Any of the gear or items equipped on your character or in your inventory is automatically stripped from the hero and mailed to your non-Seasonal characters, similar to the rollover process that occurs with your stash space when a Season ends. Accomplishments like achievements, crafting recipes learned, artisan levels, or unlocked stash tabs are left behind as part of your non-Seasonal progression. However, personal records like your character name or time played are retained and carry on through your Seasonal adventures.

There are a few things to keep in mind when using Season Rebirth:

  • Gear mailed to your non-Seasonal characters is only available for reclamation for up to 30 days from the time it is mailed!
  • You may only Rebirth up to three characters per Season.
  • Hardcore characters who have fallen are not eligible to use the Season Rebirth feature.

How Do I Claim My Gear?

If you Rebirthed a character, simply log onto any of your non-Seasonal characters that match the game type of the character you Rebirthed. For example, if you used the Season Rebirth on a Hardcore non-seasonal character, you will need to log into another Hardcore non-seasonal character to claim your loot.

Just as with the end of season rollover, your gear will be found in your in-game mail, located in the lower left-hand corner of your screen.

We hope that you have been enjoying Season 5 and look forward to seeing where your Seasonal Journeys take you!

Second Patch 2.4.0 Technical Patch Arrives

Hotfix is on the way to fix data from the Kanai's Cube bug

Diablo III Patching
A minor technical patch rolled out Tuesday, to fix a few issues with the client. This is the second of the Patch 2.4 minor patches to arrive, after the first one a few weeks ago. The Diablo III servers had login issues after the server maintenance, giving error 395002 and preventing characters from logging in, but that was fixed after about 4 hours. A hotfix is also being prepared, to restore data for accounts that lost Legendary powers in Kanai's Cube back in December.

Patch 2.4.0 Minor Patch
Like the first minor patch, this one patched a few bugs with the client itself. The small patch took the Diablo III client up to version
An additional minor patch was deployed today, providing a few minor bug fixes:

  • Fixed an issue that prevented users in certain regions from logging in.
  • Fixed an issue that caused the Diablo III client to take an extended period of time to terminate after the game has been closed.

As with previous minor updates, there are no gameplay or balance changes going into this patch. Thank you for your patience and understanding while we worked to resolve these issues.

Hotfix Incoming for Kanai's Cube Restoration
Back in December a nasty bug ended up deleting the extracted Legendary powers from the Kanai's Cube artisan, for many accounts. While that bug was fixed so that it wouldn't continue to happen, there are still many accounts that lost extracted powers. An upcoming hotfix will go through those accounts, and try to restore the deleted Legendary powers.
We’ve developed a new hotfix that does some work behind the scenes to attempt to reconstruct some of the data lost due to the Kanai’s Cube bug last December. While this fix is intended to examine past data and restore missing legendary powers, some powers may not be restored if they were gained between December 1st and December 17th. Players do not need to do anything to activate this fix, and those who did not experience any missing powers, or had them restored through a rollback, will not be impacted. No in-game progress will be lost as a result of this hotfix.

Season Rebirth Non-Reversible
Patch 2.4 brought the handy Season Rebirth feature. A hero that is selected for rebirth is transformed into a level 1 Seasonal character. Paragon levels, completed achievements, and other accomplishments from that character all stay on the non-Seasonal side, and that hero's gear is mailed over as well. This is a convenient way for players to select a hero to play in a Season, without having to delete and recreate it. As seen by a player who accidentally selected the Season Rebirth for a character, this process can not be reversed! There is a warning when choosing the Season Rebirth process; be sure to pay attention to those, so you don't accidentally rebirth a hero you didn't want to.
Hi Zezariz,

Unfortunately Customer Support doesn't have any way to undo the Rebirth process. :( Once a character has been reborn into a seasonal character, it cannot be reversed. The Support Site likely didn't have an appropriate drop-down as it's something we wouldn't be able to assist with.

No Community Buffs or Firebirds Changes in Season 5

The Season will run without major changes from buffs or Set updates

Diablo III Community Buff
Diablo III fixes this week take care of issues that cropped up in Patch 2.4. The Battle.net servers received a round of hotfixes, and a small technical patch is rolling out for the game on the Xbox One and PS4 consoles. Other big issues are being looked at, but will not be fixed during Season 5, and no community buffs will be provided this Season.

No Bonus Buffs in the Season
Developer Wyatt Cheng answered the question: will there be any community buffs this season? The design team has decided not to add those buffs during Season 5, to skip the negative side effects of the gameplay that accompanies that type of temporary buff.
Hey guys – just wanted to pop in and say that we don’t have any community buffs planned for this season.

The main reason is the one highlighted by other members of the community - while 2x buffs are super exciting while they’re active, they have negative effects at other times. The biggest is how demoralizing it can feel if you miss out on the community buff. One of the strengths of Diablo is when players feel they can play on their own schedule, when they feel like it. The 2x buffs really detract from a sense that any time is a perfectly good time to play. It can also cause people to burn themselves out trying to get the most out of the buff.

Firebird's Finery Unchanged for Season 5
The Wizard class set Firebird's Finery saw the set bonuses overhauled in patch 2.4. As discussed in a reddit thread, there are multiple issues with the way the set bonuses currently work. There won't be any changes to the set during this season, but it will likely get an update in the next content patch, for Season 6.
Just a quick update on this one:

The issue with Firebird's Finery 6-piece bonus is currently under investigation. We don't have an ETA for a resolution at this time. However, any fix we may implement would likely result in a reduction in power for the set. For this reason, similar to the situation with Raekor's/Furious Charge, we will not be addressing this issue for the duration of Season 5.

Paragon Button Over Buffs
An interface tweak that may show up in a future patch is a change to the location of the Paragon button. With the revamped buff bar, that blue button can often show up at just the wrong time, making it hard to see important buffs.

Urshi NPC Dialogue
Another change expected in a future patch will dampen the messages from the NPC Urshi, who shows up at the end of a Greater Rift.
We totally understand Urshi's dialogue can get a little... trying after a few dozen consecutive runs. We plan on addressing this in a future patch.

My running theory as to why this started happening is that Urshi really just wants to be heard. I'm sure it gets lonely in those rifts!

Patch 2.4.0 Hotfixes
Four hotfixes arrived on the Diablo III servers this week, taking care of issues involving monsters, skills, and items.
More hotfixes! We've applied the following fixes as of today, January 27th.


  • Fixed an issue where Armor Scavengers (Primordial Scavengers) would not lose their armor when hit by pets. (1/27)


  • Ray of Frost

    • Black Ice

      • Fixed an issue that caused the Black Ice rune to stop functioning. (1/27)

Demon Hunter

  • Impale

    • Fixed an issue where the 6 piece Shadow's Mantle set bonus would cause Impale to inherit the damage type of an equipped weapon when being used with Convention of Elements. (1/27)


  • Wreath of Lightning

    • Fixed an issue that caused the movement speed bonus provided by a rank 25 Wreath of Lightning to stop functioning. (1/27)

Console Ultimate Evil Edition Patch
A small technical patch has been released for the Ultimate Evil Edition on the Xbox One and PlayStation 4. This fixes some stutter and other game performance issues that showed up on those consoles with patch 2.4.
We're currently on track to patch the PS4 and Xbox One versions tomorrow, January 29th, to address the performance issues introduced after Patch 2.4.0. Once we've released the patch, simply ensure that you're connected to either your PlayStation Network or Xbox Live account, and the patch will be made available to your console.
I've confirmed that the patch has begun to deploy, but when it actually gets pushed to your console can vary somewhat. Keep an eye out!

Kanai's Cube Powers on Legendary Items
Finally, a quick reminder about the subtle cosmetic update to the display of Legendary powers that can be used in Kanai's Cube. The orange icon next to the Legendary power description has 3 versions, depending on the usage in Kanai's Cube. Players can learn the different styles of that icon, to see at a glance whether or not a Legendary power still needs to be cubed.

Engineering Diablo III's Damage Numbers

A deep dive into the newly updated damage numbers display

Diablo III Damage Numbers
The optional damage number display in Diablo III received an overhaul in Patch 2.4. The changes include new abbreviations for the very large numbers of damage being done in the game, and special colors for highlighting the top 5% of damage done. Community Manager Nevalistis wrote up a lengthy post explaining just how the system works, and the decisions made along the way to the final display. It's a great read to learn more about the behind the scenes work that goes into a game as complex as Diablo III.

To work in software development, whether it’s for business, entertainment, or your favorite video game company, is to know that simple problems don’t always have simple solutions. Game development is, in a word, complicated. There are thousands of moving parts where the smallest iteration can cause weeks of reversions and backtracking. On the outside looking in, it’s tempting to ask, “Why not just fix it?” That’s a bit like asking a baker why they can’t just substitute sugar for sucralose. The answer is similar across the board; “It’s not that simple.”

Numbers – How Do They Work?

In Diablo III, there’s lots of information thrown at the player. Let’s talk numbers. You see them everywhere! They’re on your gear, they’re in your character profile, and they float around your nephalem’s head while you’re in combat. Behind each of those digits is a huge amount of tech that makes them behave the way that they do.

We heard a lot of player feedback that combat numbers were starting to be overwhelming or difficult to comprehend in moment-to-moment gameplay. In the past, large numbers were exciting to see because they stood out above the rest. How do you bring back that emotional appeal without making players feel like they have lost power?

Patch 2.4.0 introduced a couple of new features to address this. First, we’ve introduced a new in-game option to truncate numbers and display them using abbreviations. Second, we’ve added an entirely new feature that highlights some of your largest damage numbers in a new color. Each of these additions presented their own challenges when we went to implement them; some were design issues, others created localization concerns, and at the end of all these decisions, the result needed to look good.

Initially, we had the idea of highlighting the top 5% of numbers you’ve generated in the last few seconds. The first problem with this approach was that every build is different, especially when it comes to how each dishes out damage. Some pump out small bursts of floating numbers over time while others barrage your screen with a constant stream of information. In our first pass, another issue that arose was that the new system didn’t accommodate expected fluctuations in damage dealt. Take a Power Pylon, for example, where your damage is temporarily augmented. After the Pylon ends, you’ll still want to know when you’re dealing notable damage.

We developed our algorithm over time to account for these outliers, settling on the following rules for which numbers appear in orange:

  • Damage numbers must be over 10,000 to be considered
  • If the damage number to be displayed is larger than the last that was displayed in orange, then display this new number in orange
  • Decay the value of the largest number by 3% every second
    • This reduces the likelihood that you’ll go on too long without seeing any highlighted numbers
  • Ignore the first 10 large numbers
    • This allows for the system to calibrate itself
  • If no damage has been dealt for 10 seconds, reset the system

Where Are My Billions? – Challenges in Localization

If you’ve played the latest patch, you may have already seen our new damage abbreviations. We’ve seen a lot of questions, primarily from our English-speaking audiences, about why we measure in millions, but skip counting in billions.

There are a few reasons, but one of the most important is localization. Diablo III is a global game, published in 13 different languages, so when we make a design decision that affects the written word (or, in this case, written number), we have to remain cognizant of what that change will mean in every iteration of the game. While you might think numbers would be the easiest thing to translate, that couldn’t be any less true.

Left: English language numbers. Right: Korean language numbers.

Here’s an example where what might look like a simple translation can get complicated. Some languages, like Spanish or French, do not commonly use a unique term for “billion.” They instead refer to that amount as what literally translates to “one thousand million” rather than having their own word. In terms of etymology, this is a result of both American and British English evolving the word “billion” to mean “one thousand million” rather than the “one million million” it originally represented.

It gets even more complex when looking at languages like Korean or Chinese, where large numbers are grouped on a different scale. For instance, in English, the nomenclature of a number changes with every third place, such as thousands, millions, billions and so forth. In Korean, the naming convention of a number instead changes every fourth place, using a method called myriad squared. This is because in Korean, numbers are grouped every ten-thousand fold instead of thousand fold.

This issue is compounded by punctuation use. Not every language uses commas as breaks in numbers. Some use periods instead, which is very common in Europe, and others don’t use any punctuation at all.

Left: Korean gold count. Right: French gold count.

As numbers in Diablo III grew and we decided to add in numerical punctuation, we needed a way to elegantly “translate” where—and when—this punctuation would appear for each localization. Our code uses a library called ICU, or International Components for Unicode, which provides a great amount of support for localizing software. ICU can be used in a number of ways, but for this feature, we took advantage of its ability to take a number and a locale (such as United States English, French, or Korean) as input and give back a properly formatted number for that locale as output, complete with any periods or commas. Our Localization team also keeps a table that shows what numbers each region chooses to publish and the end result.

An example of one of our localization tables, designating which language truncates at what point.

Some localizations opted to abbreviate more or less, mostly out of cultural preferences. There’s a real psychology behind player satisfaction and the actual length of the numbers you’re seeing, and player preference varies on both personal and cultural levels. For example, in English, we opted not to abbreviate in the low millions because seeing “1,000,000” is much more satisfying than “1M.” Skipping the billions place also helped with this, as seeing “1,000M” tells a much more exciting story than “1B.” Of course, number size isn’t the only consideration; the visuals, colors, and movement all play a key role as well.

Making Numbers Pop – Refining Visuals

It’s important to make sure that when a player sees a number, they can quickly understand the implication behind it and what it means to them at that precise instant. In Patch 2.4.0, we aimed to provide even more in-combat information than ever before. This is where those Critical Hit highlight numbers come into play.

Look at that beautiful crit!

Simply changing the color was one of many ways we could have presented this information. We asked ourselves a lot of questions about how was best to communicate these big hits. Do we make these numbers bigger? Have them path differently? Make them flash? Do they hang on the screen longer? Or do we just give them a different color? How do you decide which of these options is the right one?

We gravitated towards color because we could present this new information to our players in a drastically different way that passed other user accessibility concerns. Orange numbers stand out; they’re not something you’ve seen before, so subconsciously you pay close attention to them.

Orange also passes the colorblindness-friendly test. When you’re looking at a color wheel, orange is in a different realm than the other colors we currently use for other information. This way players that are colorblind can tell something’s new, too!

When we look at changing colors in our interface, our artists take a look a three options for variation: Hue, Saturation, and Lightness. This is part of what’s called the HSL color space, a common digital standardization for the color wheel.  Each aspect is key to adjusting a different emotion or evoking a new response from the player. Do we want to change the mood? Then we adjust hue. If we’re shifting an image from being juicy to more flat, then saturation becomes key. How about drawing attention or driving it away? Lightness becomes the go-to.

As an example, some of the most critical information in the game is how much healing you’re receiving. Healing is literally your life force, and we want it to be very visible. That’s why that information is some of the brightest in the game. We wanted critical hit information to be extremely visible as well, so we played a lot with its lightness levels to make sure you always know when your next big damage spike occurs.

Bring It All Together

When we talk about the Diablo III team, it’s easy to first think of our developers who tweak the way a class or an item functions, or put cool, new features in to explore. However, there’s so much more going on beyond what your hero is wearing or wielding, and our artists, engineers, localization experts, and so many more help us ensure everything comes together smoothly for all of our players around the world.

We hope you’ve enjoyed this in-depth peek behind the scenes of a small feature that, under the hood, is deceptively gargantuan! It’s a privilege to come in every day and work on this game, even when it’s on the little details. Thanks for reading!

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