At the end of each round

Trigger · combat

This can fire more than once in a battle, which is what makes stacking a question: whether a second application adds to the first or refreshes it depends on the ability.

Token
RoundEnd
Game code
19
Game name
trig_round_end
Timing
Combat
Cadence
Repeats — can fire every round
Effects last
To the end of the battle, unless the ability names a round count