So, this looks interesting, and what I'm hearing here is that the main issue -if it can be called such- currently is that you need someone that can actually threaten Terra consistently? Because I have a couple character possibilities that could do the trick, a few villains and definitely one anti-hero (all of them from Jojo's Bizarre Adventure).

I'm currently leaning towards Diavolo (big maybe here, mostly only a threat to everyone else and really hard for her to hinder), Kira Yoshikage (huge threat to literally everyone) or Bruno Bucciarati (funni zippers go brrr). I'm mostly interested in Bruno, since his is the only powerset of the three that doesn't affect time in some manner, so he shouldn't suffer the likely innate nerfs the other two will, but I may drop more than one sheet and see anyway how much the former two will get hit.