As the marker reached him, Leon's expression quickly changed from proudful to horror as he seemed just realized how the counters work.
The green skull appeared again on top of him and his units, and as he knew that it would be Rugal's last turn, Leon quickly gave out a command as an interrupt.
"WAIT! I INTERUPT! ACTIVATE RUGAL'S CAT RECOLLECTION!"
Ahli was hoping that Carta would not allow it, but unfortunately, it did.
A card was drawn from Leon's deck and landed on his hand before a notification was heard again from Carta.
A triggered event is an effect that happens at certain moments or when a condition is met. In the case of this battle, it was the beginning of Leon's turn, where Poison Counters that were attached to him and his units had stated that it should be added by the beginning of his turn.