Reactions split into two families — ones that multiply a hit's damage and ones that deal damage on their own — and which family you're triggering decides almost everything about how you build a team.
Elemental reactions split into two families: amplifying reactions (Vaporize, Melt) multiply the damage of the hit that triggers them, and transformative reactions (Overloaded, Electro-Charged, Bloom, and others) deal their own damage independent of the attack that set them off. Knowing which family a reaction belongs to tells you whether to build for attack damage or for Elemental Mastery — the two stats reward completely different reactions.
Amplifying reactions take an existing attack and scale it up. Vaporize (Hydro touching Pyro) and Melt (Cryo touching Pyro) are the only two. The multiplier depends on which element lands second: applying Pyro onto an existing Hydro or Cryo aura gives the bigger multiplier (around 2x), while applying Hydro or Cryo onto an existing Pyro aura gives the smaller one (around 1.5x). Because the reaction rides on top of a real attack, characters built for amplifying reactions still want crit rate, crit damage, and attack — Elemental Mastery adds on top of that, it doesn't replace it.
Transformative reactions are their own attack. Overloaded (Electro + Pyro), Electro-Charged (Electro + Hydro), Superconduct (Cryo + Electro), Swirl (any element + Anemo), and the whole Dendro family below all fall here. Their damage is calculated from the triggering character's level and their Elemental Mastery — not their attack stat, and the hit can't crit. This is why a support character with barely any attack can still make a transformative reaction hit hard: level and Elemental Mastery are all that matter.
| Reaction | Elements | What it does |
|---|---|---|
| Vaporize | Hydro + Pyro | Multiplies the triggering hit's damage (amplifying) |
| Melt | Cryo + Pyro | Multiplies the triggering hit's damage (amplifying) |
| Overloaded | Electro + Pyro | AoE explosion damage, knocks back most enemies |
| Electro-Charged | Electro + Hydro | Damage over time while both auras persist |
| Superconduct | Cryo + Electro | AoE damage, lowers enemy Physical RES |
| Swirl | Anemo + any other element | Spreads that element's damage and aura in an AoE |
| Crystallize | Geo + any other element | No damage; drops an elemental shield instead |
| Quicken | Dendro + Electro | No damage; applies the Quickened status |
| Aggravate | Electro on a Quickened target | Boosts the Electro attack's damage |
| Spread | Dendro on a Quickened target | Boosts the Dendro attack's damage |
| Bloom | Dendro + Hydro | Spawns a Dendro Core that explodes on its own after a delay |
| Hyperbloom | Electro hits a Dendro Core | Core fires a homing projectile for Dendro damage |
| Burgeon | Pyro hits a Dendro Core | Core explodes immediately for AoE Dendro damage |
| Burning | Dendro + Pyro | Continuous AoE Pyro damage, can ignite nearby flammable terrain |
Characters and artifact sets that push Elemental Mastery aren't chasing a side stat — they're scaling the actual damage number a transformative reaction deals. The relationship isn't linear: early points of Elemental Mastery add a noticeably bigger damage bonus than the same number of points added once you're already stacked high, so a dedicated reaction character gets diminishing returns rather than gains that keep pace forever. That's also why teams built entirely around triggering Overloaded, Electro-Charged, Hyperbloom, or Burgeon load Elemental Mastery on a support character instead of splitting it thin across four.
Amplifying reactions get Elemental Mastery too, but there it's added on top of the 1.5x/2x base multiplier rather than being the whole source of the damage, so a Vaporize- or Melt-focused DPS still wants crit and attack first.
Every element you land on an enemy leaves an aura — a lingering tag that says "this target is currently wet," "currently electrified," and so on. Underneath that aura sits a hidden gauge value that decides how much of that element is actually present. A weak attack can apply an aura too small to fully consume in the reaction it triggers, and a strong attack can wipe out an aura that a smaller hit would have only partially reacted with. This is the actual reason a reaction "doesn't go off": the aura either isn't there yet, has already decayed off the target, or gets consumed faster than you're refreshing it, so your next hit lands on a clean target instead of a reactive one.
Auras also decay on their own over a few seconds, faster for a small application and slower for a large one, so timing matters as much as elements: a Pyro hit that lands two seconds after the Hydro aura already expired triggers nothing.
For Vaporize and Melt, the order the two elements land in changes which multiplier you get — Pyro landing on an existing Hydro or Cryo aura is the strong direction, the reverse is the weaker one. This is the whole reason team-building guides specify "apply Hydro, then hit with Pyro" rather than treating the two elements as interchangeable: swap the order and the same two elements produce a noticeably smaller number.
The same logic runs through the Dendro tree. Quicken has to exist on the enemy before Electro can trigger Aggravate or Dendro can trigger Spread off it — hit with Dendro and Electro in the wrong sequence, or too far apart, and you get plain Catalyze-adjacent damage instead of the boosted follow-up. Bloom needs a Dendro Core to exist before Electro or Pyro can turn it into Hyperbloom or Burgeon, so the Hydro-Dendro hit that creates the core has to land first.
A team comp is really a decision about which family of reaction it's chasing, and that decision should drive every character slot: pick amplifying reactions (Vaporize, Melt) when your main damage dealer already has strong attack and crit, and stack Elemental Mastery on someone else. Pick transformative reactions (Electro-Charged, Overloaded, the Bloom branch) when you want a support character's off-field damage to matter, since level and Elemental Mastery carry that number regardless of the support's own attack stat. Either way, check which enemies you're fighting before committing — some resist specific elements or reactions, and a weapon that boosts Elemental Mastery is wasted on a team built entirely around amplifying reactions, just as crit-focused weapons are wasted on a pure transformative-reaction support.