Werewolf is only useful for Rogue Sneakhit. If you are rogue, 3x werewolf 10 star is a possibility.
Standard set-up for purple slot is 2-3x gazing golem card. In ktos, after gazing golem and canceril nerf, it is also common to go 1-2x gazing golem + 1x canceril card.
Some more options (from first post):
Suggested cards:
Red = Centaurus (AoE Hacka build),
Glass mole (burst with potion),
Prison Cutter (Stormbolt Bleed),
other viable red cards (Moa damage vs devil type).
CC card: Froster lord card.Blue = Zaura or Nuaele (best cards for Blue).
Other card recommendation: Armaos card.Green = Any card, except INT bonus cards.
Purple = 2-3x Gazing Golem card (pain barrier effect!).
Rogue specific: werewolf card works with rogue Sneak Hit.