Vaal Side Areas & Vaal Skills
All About the Vaal
Once in a while during your travels, you'll run across a Vaal Side Area, identified by a pulsing red glow over an entranceway to an area not featured on your map. Vaal Side Areas are short sprints that contain some bonus loot at the end, and are worth doing whenever you come across them.
Each Vaal Side Area has a modifier applied to it, the same as the modifiers you'll eventually find on the Maps you run in the endgame. They'll also have a boss at the end next to a special interactable object called a Vaal Vessel. Killing the boss and looting the vessel can yield three types of reward:
- Sacrifice Fragments (Sacrifice at Dawn/Noon/Dusk/Midnight): These are used as a set to unlock a boss in the endgame. Sacrifice at Midnight is the rarest of the set.
- Corrupted items: Corruption can, among its many other effects, scramble the affixes and sockets on an item. This can, if you're lucky, result in exceptional levelling items that can speed your combat up significantly. If you're really lucky, you can even find a 6-link item at a much-higher-than-usual rate, since Corruption has about a 1-in-150 chance to 6-link an item.
- Vaal Skill Gems, special Skill Gems discussed further below.
The appearance of Vaal Side Areas is random, but they're not very rare - you'll see one in maybe 1 in 10 areas, about once or twice per Act.
Vaal skills are special versions of regular Skill Gems that grant a greatly empowered variant of the normal skill. For example, a regular Fireball gem throws a single Fireball; a Vaal Fireball, on the other hand, shoots a spiral of 32 Fireballs in all directions, obliterating just about anything nearby. Similarly, a regular Summon Skeletons summons a single Skeleton to fight for you, a Vaal Summon Skeletons raises a whole army, complete with a Skeleton General that buffs your other minions.
Unlike most regular skills, Vaal skills can't be spammed. They must be charged with Souls before they can be used: most skills take between 10 and 50 Souls, and you gain 1 Soul per enemy you kill, plus some souls as you damage bosses. Once a Vaal skill is used, it will prevent you from gaining souls for the next few seconds (the exact duration depends on the skill), meaning that Vaal skills generally can't recharge themselves by slaughtering a whole screen of enemies. (In the past, they could recharge themselves, which led to them being reworked.) This Soul Gain Prevention is increased by increases to Skill Effect Duration if the skill itself has a duration.
Each Vaal gem has a cap on how many Souls it can hold; for most (but not all) Vaal gems, this cap is enough for one use of the skill. Soul counts are stored per-zone and per-skill, meaning that you will start with an empty Soul counter upon entering a new area. This can be particularly relevant for certain bosses not found in larger areas.
A Vaal skill gem grants both the Vaal version and the regular version of the skill in one gem. As a result, at equal Quality and Level, there's no reason not to use the Vaal version over the regular one if you're fortunate enough to find the Vaal variant of your main skill.
You can use more than one Vaal skill gem, but they don't gain souls simultaneously - any time you gain a soul, it will be randomly assigned to one of the Vaal skills that isn't at its full soul capacity. Using any Vaal skill applies the soul-gain cooldown to all Vaal gems, so you can't charge one Vaal skill by killing enemies with another.
Any effect that affects the parent gem will affect the Vaal version. So, for example, anything that provides a special effect to Fireball would provide the same effect to Vaal Fireball. This is most notable in the cast of certain skill-modifying Jewel items.
All Vaal gems are inherently Corrupted, meaning that you cannot use currency items on them. In particular, it is fairly difficult to get a high-Quality Vaal skill gem, because you can't use Quality-increasing Gemcutter's Prisms on them. Corruption does not prevent levelling up a gem, so you can still do that.
Most of the time you'll get your Vaal skills as drops in Vaal side areas, but there are other possible sources. Most notably, Corrupting a skill gem by using a Vaal Orb on it has a chance to yield its corresponding Vaal skill gem. This is the primary means by which you can get a high-Quality Vaal gem.