Primer on Diablo 3's skill slots

Diablo 3 is different that the previous games in the series in many ways. One of them is the way skills can be accessed in combat. Due to the way the skill system works (you gain new skills automatically and for free as you level up), Blizzard wanted to limit skill spamming and to prevent people from facing every potential situation by simply having easy access to a large and diverse pool of skills.

To this end they implemented the current skill-swapping and skill slot system.

In Diablo 3 you are limited to a maximum of 6 skills that you can use in combat. The limitation is artificial and is given by the available skill slots. You get 2 slots for your two mouse buttons (left and right) and 4 additional slots (by default assigned to the keys 1-4). In the beta, only 2 of the latter are available, for a total of 4 active skills. That's because additional slots are unlocked at higher levels.

In addition to the 6 active skills you can also assign 3 passive skills. Once again, these passive slots are enabled progressively as you level.

There's also a special slot which is exclusive to healing potions. By default this is accessed by the "Q" key.

You can easily determine at which levels these slots become available by visiting the skill calculator for any class. If you don't feel like going there, here's the breakdown:

Active Skills
Level 1: left mouse button
Level 2: right mouse button
Level 4: "1" key
Level 9: "2" key
Level 14: "3" key
Level 19: "4" key

Passive Skills
Level 10
Level 20
Level 30

You can, of course, change the default key assignments for the active skills if you wish. As you can see, by level 30 you will have access to all the possible slots. There's no simple coincidence that at level 30 you will also be finishing the game in Normal difficulty. When you move on to Nightmare you should be able to juggle all 6 active skills as well as all 3 passives.

Skills can be swapped into these slots anytime you wish, whether in town or outside. There's a catch though. In town skills that have been freshly swapped can be used immediately, while outside town the fresh skill will have a 30 second cooldown. That's not a big deal at all, considering that you can use your other skills in the meantime. An additional limitation is that skills which are on cooldown (some cooldowns are several minutes in length) cannot be swapped until the cooldown is over.

When Blizzard recently overhauled the skill system, they also came up with a new interface for assigning those skills (and skill runes), as well as the concept of Guided vs Elective Mode. I will admit that this interface isn't the most intuitive. A lot of people have stated that it needs work and I agree. For what it's worth, I've gotten used to it and it doesn't bother me terribly.

Blizzard breaks down skills into different types. Each class has primary, secondary and Defensive skills. Typically, primary skills (left mouse) are resource generators, while secondary skills (right mouse) are resource spenders. This means that (depending on the situation of course) you can open with your secondary skill for a big nuke and when your resource is depleted you can switch to the primary skill to replenish said resource. The Defensive category ("1" key) is just that: skills that help you survive.


The next 3 skill types ("2", "3" and "4" keys) vary for each class individually. For example, the Barbarian has Might, Tactics and Rage categories, while the Demon Hunter has Hunting, Devices and Archery.

The game starts with Guided Mode as default. What this means is that when a new skill slot becomes available, you will only be presented with skills that match the related category. For example you can only assign primary skills to the left button, secondary skills to the right button, Defensive skills to the "1" key and so on.

While many people were at first horrified by this so-called "nanny mode", I will admit that it isn't as bad as it seems. First of all, if you so wish, you can choose to enable Elective Mode (Options > Gameplay > Interface) which allows you to assign any skill to any slot you wish. Second, if you start a new class you haven't played before, or if you're just getting the hang of the game, Guided Mode is a very decent tool for teaching you the ropes.

With Guided Mode, you will learn which skills generate resources, which consume them, which are defensive and which can help you in other ways. Mixing skills together from the start could prove confusing and might even drive people away from classes such as the Demon Hunter which uses 2 resources.

I urge everyone who starts playing Diablo 3 to skip Elective Mode for a while and simply let the game guide you. Once you get the hang of it, you will know when the time is right to assign your own skills. I finished the beta with all 5 classes and only then did I try Elective Mode on one of them.

This is it for my primer on Diablo 3's skill slots. If there's anything I have missed, please feel free to drop me a comment.

Disclaimer: This article is written partly in response to Diablo 3 Gold Guide's April blogging carnival. I say "partly" because I am planning to tie this into a series of future articles.