Reactionary Players can use their reaction only when it is not their turn; the trigger for their reaction must occur during someone else’s turn (including at the beginning of it). For example, a spellsword uses her bonus action to drink a potion of healing, then her action to make a melee on an enemy fighter while they both stand on a high bridge. The fighter uses his reaction to shove the spellsword off the bridge. Since the spellsword has already used her bonus action in her turn, she can’t cast feather fall as a bonus action. However, at the start of the next character’s turn, the spellsword could then use her reaction to cast feather fall well before hitting the ground. Conversely, if the spellsword used her action to cast a fireball against a group of targets but an enemy wizard used his reaction to counterspell her fireball , the spellsword would not be able to use her reaction to counterspell the counterspell, as his counterspell occurred during her turn and she cannot take a reaction until it is no longer her turn (by which point the fireball has already been successfully countered.) Added to House Rules 18 Feb 2024; updated
Tag: counterspelling
Counterspells If a character uses their reaction to identify a spell being cast and succeeds at their Arcana check, they can immediately counterspell in the same reaction. Added to House Rules in 2023.