Plague or Deathslinger?
I already have corrupt intervention from shrines, no perks from deathslinger (although I am aware that none of them are fantastic). I quite like Plague's other perks with infectious as a good flashlight save counter and snowball perk, and dark devotion on paper looking to be a possibly niche, but fun perk. Deathslinger looks fun, but none of his perks are really worth the 9000 shards. Plague's abiliy looks okay-ish, but not as fun as Deathslinger. Both of them seem to be on the same level of power though, so it is hard to decide.
If you have a different opinion on level of power or strength of perks, it is most likely because i took a long break from the game, but have found it fun again afterwards especially with the crown grind (which didn't take that long but got the ball rolling).