I aggre with Mariner (took yours for a spin earlier today).
Best thing about her is you don't need to spend shards on her, GPDog dmg is NUTS in compare with hers.
Said that, quoting Sparton:
The Sentinel Corrupt Rescuer joins its fellow allies from the Brave New World as a new 4* Sentinel in Legacy of the Beast. She is a physical attacker who deals extra damage based on negative effects on her, she can transfer all negative effects from her allies to herself, and automatically heals allies based on the amount of negative effects on her.
"deals extra damage based on negative effects on her" (???)
I don't know if this is a typo, or her basic is missing something.
If her basic, worked as advertised, hitting harder with each negative effect on her, I can see she getting some love on the arena. (versus Val teams for example, let that pesky shield fill your team with debuffs, steal then with SCR and boom.)
or
If her power move, healed right after she steals the debuffs (since she gets an extra turn).
Cheers! Ed!