Attacks » Word of Ruin
Both players have 1 prize left. Player-A uses Galarian Slowking V's "Word of Ruin" attack. Player-B attacks Galarian Slowking V with enough damage to KO it with the same Pokemon that got hit by "Word of Ruin". Who wins? Or is it a tie?
The KO from Player-B's attack happens before the end of their turn, so the game is over before Word of Ruin's effect gets to happen. Player-B wins.
Source: Chilling Reign FAQ; TPCi Rules Team (2021-06-17)
Attacks » Word of Ruin
When I use Galarian Slowking V's "Word of Ruin" attack, is my opponent's Pokemon still Knocked Out if they retreat it during their next turn?
Since it is an attack effect on the Defending Pokemon, the effect is removed if that Defending Pokemon is no longer Active.
Source: Chilling Reign FAQ; TPCi Rules Team (2021-06-17)