Miss Valeria, Bureau Chief

Hexproof, vigilance, undying
Other Agents you control get +1/+1.
Whenever your opponent casts a nonlegendary spell, they lose 1 life.
It Was Here Just A Moment Ago! {2}{w}{b}: Permanents your opponents control lose hexproof, indestructible, shroud and ward until end of turn.
They Never Saw Him Again {2}{w}{b}: Exile target opposing creature.

She's everywhere. She's always been there. You've seen her before. You just don't remember it.