Last week, we shared the Part One of a news series where one of our game designers, Hrishi, discussed the development process for the new Legion Jewels and their keystones. We're sharing part two today and will share the final part next week! We hope you enjoy it.

Starting Keystone Design

Designing three keystones for all five Legions wasn't too bad, though. We had a wealth of ideas to pick from and the theming of each Legion was quite strong. Also, coming up with compelling designs was easier when we weren't constrained by what was already on the tree. The only concern was that keystones might take a fair amount of iteration and we had to get them implemented early on so that we could test them. Once again, I looked around the office for ideas on what they could do and compiled a good list to then cull from. It was very important to implement them as early on into the development cycle as possible in order to get the time to iterate on them and test.

The biggest question in the room was really, what makes a keystone? What qualities are desirable and undesirable for a good keystone? My first step was to establish a set of ground rules that keystones should follow.

• Keystones should follow the premise of "give something, take something"
• Keystones should be "unique", such that they provide something either unobtainable from other sources, or at least very hard to find.
• Keystones should attempt to circumvent the basic rules of the game.
• Keystones should significantly impact the way your character is played or built.
• Keystones should be somewhat self-contained, in the sense that it should "work" without needing a combo of something else incredibly specific. Naturally, keystones should of course encourage building for them, but it should not be too specific.

Of course, not all keystones on the tree follow all these rules. In fact, most will deviate from a few of these rules in some way. But I wanted to try to stick to as many as I could. If a design deviated from too many of these rules, it might indicate that we should try something different. Another important part that I tried to stress was elegance, which is to say, keep as few stats on the keystone as necessary and make it more or less instantly understandable as best I can.

Armed with all these rules and preparation, I along with many others ended up putting together a staggering number of keystones that I hope are very fun for players to experiment with. Below, I will go into each individual keystone that made the cut.

Vaal

Divine Flesh


This was one of the first keystones to be done, but it went through a fair number of changes before the final version. Originally, this did not have the bonus to maximum Chaos Resistance at all, and simply read as follows.

Your maximum Energy Shield is 0
100% of Elemental Damage is taken as Chaos Damage

The intent behind this was to make it so you had to stack no Elemental Resistance at all, but instead your character needed to max out your chaos resistance instead. Of course, we were making the change such that this applied to DoTs too. But of course, such a design had problems and it comes down to Chaos Inoculation.

While CI is probably my favourite keystone in the game, I cannot deny that it certainly limits design space in many ways. Due to the existence of CI, making a pure chaos damage boss fight is usually not something we can ever do. Well, this keystone took that problem and added it to every single pure elemental boss fight in the game. Worse, with this keystone, it rewarded respecing to get CI before any pure elemental fight.

Okay, this is a significant problem and we obviously couldn't let this go into the game as is. After a discussion we reasoned that we didn't necessarily need to have all your damage be taken as Chaos, just a significant amount. In addition, we could provide some maximum Chaos Resistance which is an incredibly rare stat to help with this property. The keystone changed from being something that caused a player to not stack elemental resistances at all, but instead now took the form of a powerful way to mitigate elemental damage altogether when you stacked enough chaos resistance. This proved to be quite fun and an interesting incentive to stack chaos resistance and ended up being the version that got released!

Eternal Youth


Another keystone done very early on, the idea behind this goes a while back. I had wanted to make a unique item several leagues ago that caused your Life to recharge instead of Energy Shield. This concept was also one of the ideas in the massive corrupted keystone document.

The reason we ended up dropping this back then was because recharge was very much Energy Shield's thing. Having Life steal it simply made Energy Shield feel less special. However, do you remember one of the rules I had made for what makes a good keystone? A keystone is the natural place to circumvent the rules of the game, and it made complete sense to do it here. We have plenty of keystones already that have Energy Shield taking aspects of Life such as Ghost Reaver and Zealot's Oath, so let's do one in reverse!

This changed very little during development, with the only change being a less severe downside in the final version. The original one in development completely prevented Life Regeneration and Leech, but that didn't seem necessary. We were also going to have the keystone give some amount of Life, but that didn't seem necessary either.

Corrupted Soul


This keystone came from a desire to further try to promote the playstyle the unique item Corrupted Energy tried to do. Since this was going to be a keystone, we could go a lot crazier and riskier with it.

This was very obviously designed from the beginning as a hybrid-focused keystone. One of the strengths hybrids have is the ability to recover two "life bars" at once, but you almost never need to. By distributing the damage amount between the two pools, you had the ability to take advantage of this. On top of this, the keystone rewarded you with some more Energy Shield that scaled off your life total as a payoff.

Karui

Strength of Blood


During a brainstorming session, an idea was pitched of somehow making your leech instead provide you a damage bonus based on how much you were leeching. While I wasn't a fan of it simply giving you some damage, I loved the notion of turning it into another defensive bonus somehow. This way you'd give up your recovery but instead gain some damage reduction based on your leech.

This keystone also barely changed during development, with one of the hardest things being how to describe this effect. It's quite simple to understand if you know the concept behind it, but as a line in the game, it's not so easy.

Tempered by War


This was one of the earlier keystones that came from one of the ideas thrown around for Vaal Avatar of Fire. Due to the earlier keystone mentioned above, Divine Flesh, we wanted to have stats such as "X Damage taken as Y Damage" also apply to DoTs. So it seemed interesting to use a similar concept in a very differently themed keystone.

In many ways, it's very similar to Divine Flesh in the sense that it provides you with potentially massive mitigation by focusing on a single resistance. However, the builds that would use this would perhaps be quite different, and the downsides attached to this keystone were extremely thematic and cool, while not insurmountable.

Glancing Blows


This one had a much longer development cycle. Originally the keystone had nothing to do with blocking at all, but instead dealt with unreserved mana. It used to read as follows (with a different name, obviously).

1% more Attack Damage per 2% Unreserved Mana

This had problems, both with rounding as well as how impactful and fun it was really going to feel. Yes, it had a "downside" attached to it, but it didn't seem very exciting and it was quite easy to math out whether this was worth it or not in the majority of cases.

A few days later, the plan to make monster blocks take a percentage of the damage instead of avoiding it entirely was going around. Of course, this made me wonder if we could have this apply to players in the form of a keystone. Once it was confirmed we could indeed do this, we came up with this design shortly after.

This keystone was very much designed in a way that builds that already were getting block capped would have no use for this keystone. It is specifically made for builds that struggle to do so. This ended up being quite fun and had a number of fun synergies along the way!

Maraketh

Wind Dancer


This keystone ended up being among the last ones to be developed. This was because originally it had a very different look. The keystone used to read as follows.

Always Deal Critical Strikes
You have no Critical Strike Multiplier

This sounded extremely keystone-y to me at the time and we went with it. Of course, this posed some significant problems, both in terms of current balance as well as the future. While the current balance concerns could be handled by adding more and more downsides to the keystone, it started to lose its elegance. But the biggest problem was the problem of this gobbling up a ton of design space and forever being something we needed to care about in the future with any interesting crit-related mechanic we might introduce.

So, the next step was to go to Kintsugi and look at its signature mod. This has always been a favourite of mine and it seemed to make a lot of sense to have it on a keystone. Of course, due to this being on a keystone, we pushed both the downside and the upside fairly significantly so it has a noticeable impact on your character. While your character build probably doesn't change too much, this has a lot of interesting gameplay elements to it!

Dance with Death


I've always loved the Bringer of Rain and its extremely impactful downside of losing your entire chest armour. This was simply taking the concept of losing a gear slot in exchange for some powerful benefits.

We had experimented a bit with "lucky" mods before, but never on a keystone. This seemed like the perfect opportunity to do this. Taking off your helmet in the heat of battle is a highly risky action and we wanted the keystone to fully reflect this in the form of a very risky keystone with some powerful payoffs.

Second Sight


This keystone also had a long development. Originally, the keystone was simply meant to reward you for blinding enemies, and allow you the ability to rely on blind a lot more. The problem was that coming up with a good downside was not trivial at all. Blind just worked really well with Evasion and Dodge. We could say "no Dodge", but then you simply don't take Acrobatics.

Eventually, someone pitched the idea of keeping the blind theme, but blinding you instead of enemies. I really liked the idea. A "blind warrior" is a well-established trope and we tried to fully bring it out here. Of course we wanted the keystone's payoff to be limited to attacks, since blind is not a relevant downside to spellcasters. Also, blind not affecting your Light Radius was done just so that it wasn't an exercise in frustration playing with this keystone, with your entire screen appearing black.