The once per turn clause on its triggered ability makes it impossible to break, and the card as it stands is almost too fair
It's pretty straightforward: Painter's Servant makes every card the same color, even cards that usually lack a color identity like lands, and then Grindstone mills your opponent out in one go
The fact is, this card completely shifts the attention of the warp mechanic: We're no longer looking at a card with a strong effect triggered when it enters, but rather it counts on leaving the battlefield over and over again
Referencing Kaldheim seems like the perfect way to bring back a card like this because of the boastful berserkers that call the plane home
The real twist of the deck was pushing populate into red
cards: If your opponent's Character has been K type, draw 1 card and give up to 1 of your opponent's Leader or Character cards 3000 power during this turn