Elemental Reactions reward you for layering elements in a fight. Land an elemental hit and it can leave an affliction on the enemy; strike that already-afflicted foe with a different element and you detonate a Reaction — a burst of bonus damage on top of the hit that triggered it.

Afflictions

Each element leaves its own mark when it lands (from an elemental weapon, a spell, or an Elemental Oil):

The Reactions

Hit an afflicted enemy with the listed element to trigger each one:

Reaction damage scales off the hit that set it off, and is capped so a lucky critical can never one-shot a boss. It rewards setup, not luck.

Stun

Several reactions can Stun — robbing the enemy of its very next action. Set up the right element, land the detonation, and you buy a free round.

Reading the enemy

The enemy panel shows the afflictions a foe is currently carrying as small icons, so you can see what's primed and plan the next element to chain.

Every class can play

Casters chain elements with their spells. Martial classes use Elemental Oils — a line of Alchemy recipes that coat your weapon with an element for two minutes, so any swing can apply an affliction and trigger reactions. See Alchemy.

Party Reactions (Patch 2.7)

In raids and dungeons, Reactions now fire off afflictions placed by any party member on the shared enemy — not just your own. A Warlock's Chill primes a Fighter's Fire for a Vaporize; one player Sunders and another Crushes. Coordinating elements across a group is now real, deliberate teamwork, and the deepest way to burst a boss. (Solo play is unchanged — you still combo off your own afflictions.)