Elemental Reactions are triggered by applying certain combinations of elemental effects on a target (monster or player). Elemental effects linger for around 9–12 seconds depending on what applied them. They are also removed by elemental reactions, though an effect can last after a reaction depending on which skill applied it and which reaction took place. Reactions have no cooldown, but skills have internal cooldowns before being able to reapply their elemental effect.
Elemental reactions have the following effects:
|Burning||+||Applies fast-ticking, low damage Pyro DoT effect.|
|Absorbs some of the target's elemental energy and drops a crystal that can give a character an elemental shield if they touch the crystal. The shield will absorb all types of damage, but it protects against the shield's element more effectively than other types of damage.|
|Applies Electro DoT effect.|
|Freezes the target in place.|
Hitting a frozen enemy with Claymore attacks or Geo DMG will cause Shattered.
|Melt||+||The attack that triggered the reaction will deal x2 Pyro DMG.|
|+||The attack that triggered the reaction will deal x1.5 Cryo DMG.|
|Deals additional AoE Pyro DMG.|
Create explosive effect: can break Geo shields and chunks (forging materials) faster.
|Deals additional AoE Cryo DMG.|
Reduces the target's Physical Resistance.
|Deals additional AoE Cryo/Electro/Hydro/Pyro DMG.|
Spreads Cryo/Electro/Hydro/Pyro debuff.
|Vaporize||+||The attack that triggered the reaction will deal x1.5 Pyro DMG.|
|+||The attack that triggered the reaction will deal x2 Hydro DMG.|
Elemental reaction damage can be increased by the Elemental Mastery of the character causing the reaction. The in-game interface shows the damage bonus provided by the character's current elemental mastery. This bonus will be applied in different ways, depending on the type of reaction.
Notable sources of Elemental Mastery include:
- Instructor's set's 4-piece set bonus grants +120 elemental mastery for the team when the character with the set equipped causes an elemental reaction.
- Sucrose's passive talents (Catalyst Conversion, Mollis Favonius) can provide elemental mastery to other team members.
- Some characters, such as Lisa, gain elemental mastery as a specialized stat starting at their 2nd Character Ascension.
- Transformative Reactions include Overloaded, Shattered, Electro-Charged, Superconduct and Swirl.
- These reactions have a base damage determined by the level of the character triggering the reaction.
- This base damage is then multiplied by a percentage determined by the Elemental Mastery of the character. The percentage can be seen in-game in the Details section of the Attributes page.
- The damage from these reactions cannot crit and is only based on level, meaning ATK, Crit Rate and Crit Damage have no impact. However, the damage is affected by the target's elemental resistance.
- Since Superconduct has the lowest base damage, the other reactions can be expressed in multiplicative term of Superconduct base damage. For Superconduct, Swirl, Electro-Charged, Shattered and Overloaded, these values are approximately 1: 1.2: 2.4: 3: 4 respectively. So it can be said, for example, that Overloaded base damage is approximately 4x Superconduct base damage (all other factors being equal).
- The reaction damage will be an additional instance of damage on top of the damage from the skill, making it difficult to discern due to the overlapping damage displayed values.
- Amplifying Reactions include Vaporize and Melt.
- Unlike transformative reactions, Melt and Vaporize replace the damage of the attack/s that triggered them.
- These reactions multiply damage of existing attacks by either 1.5x or 2x depending on which element triggers the reaction.
- Damage from these reactions can be critical and considers the target's elemental resistance.
- The damage is multiplied again by a percentage determined by the Elemental Mastery of the character. The percentage can be seen in-game in the Details section of the Attributes page.
- The bonus % to Vaporize and Melt is roughly half of that to Overloaded, Superconduct, Electro-Charged, Shattered, and Swirl, though the damage being multiplied can be much greater than the base damage of the other reactions.
- 1.5x reactions will tend to preserve the initial element for multiple hits, while 2x reactions will tend to immediately remove the initial element. 
Order of Application
If an amount of damage results from an elemental reaction, its damage scales with the level of the character who applied the last element, as well as their elemental mastery, and is reduced by enemy elemental resistance. The triggering element will be displayed on the left of reaction animation over enemy's head, while the base element will be displayed on the right.
In the case of Swirl spreading an element to an elemental slime (e.g. a pyro-infused swirl reaction hitting an electro slime), the resulting damage scales based off the level and elemental mastery of the slime, not the Anemo character, though the swirl damage itself gets its scaling from the Anemo character.
(1st ← 2nd)
|Melt||←||Damage considers additional multiplier of 2 along with additional multiplier from elemental mastery.|
|←||Damage considers additional multiplier of 1.5 along with additional multiplier from elemental mastery.|
|Vaporize||←||Damage considers additional multiplier of 1.5 along with additional multiplier from elemental mastery.|
|←||Damage considers additional multiplier of 2 along with additional multiplier from elemental mastery.|