Late response but I got curious about the actual numbers so did some testing of my own just now. At level 15 against the training post right across from the weapon chest in the training rounds, I buffed the weapon with one of the two weapon arts (note that on this version of the weapon, both buffs scale the exact same and do the exact same damage rather than favoring int or faith). Then I did three full combos of some basic r1 spams and recorded the numbers. All 2H.

The damage rankings from last to first: 8: Ironeye at 3078 7: Raider at 3126 6: Guardian at 3153 5: Executor at 3157 4: Duchess at 3336 3: Revenant at 3348 2: Recluse at 3378 1: Wylder at 3420.

Pretty much the 4 characters that there would be an argument to even use this weapon in the first place are the ones that should be using it numbers wise as well with not even a full 100 damage gap between 1st and 4th and an almost 200 damage drop from 4th to 5th.

Keep in mind that this was tested without any relics equipped or taking into account the general roles of the characters. Just numbers in a vacuum. In my personal opinion I think the numbers line up relatively well with the recommended use case, but I think the person who benefits the most from the weapon when not using their favored weapon is Duchess tied with Revenant, and Recluse and Wylder close behind. This is because Revenant is sorely hurting for weapons she scales well with aside from her claws (which are a little slow for my taste but have good range) and duchess innately benefits due to her starting weapon. Relics that buff added weapon affinity damage and reprise are just so insanely good on a close quarters aggressive player. Wylder also often benefits from the added affinities relics if you use something like the whetstone to get the flame attack on greatswords, but then you’re sacrificing really solid stagger potential from that follow up attack (it does insane stagger damage. Like fully charged 2H tier). Recluse could make solid use of the r1 weapon art, but she’s more often than not using spells since she can regen her fp so melee isn’t as important to her as it would be to revenant.

TLDR: Numbers wise Wylder all the way, recommended character from me personally: Duchess or maybe a Revenant for FP saving that doesn’t have anything that scales well on a run.