Seraphina Martel 2: This Time It's Personal
Well, before when her power was time control, she was more durable than a normal person but not so much invulnerable as able to regenerate so fast that it might as well be invulnerability, and more severe damage took concentration. I.e., she still felt pain and took damage, but she reversed her personal timeline to when she wasn't damaged.
Since it's been revealed that she never had time powers at all, regular invulnerability is probably better.
As for what's powerful enough to hurt her, I'd like to know what the general super level of the setting is. She should be on the very high end, whatever that is, but that could be anywhere from 'doesn't need a bulletproof vest' to 'may as well be a deity.' Same with strength and really everything power.
I never envisioned her as having super-speed in and of itself, just time powers that made it look to external observers as if she had supreme speed faster than anything else. You know, cheating, rather than actually being faster. But she doesn't have time powers.
Basically, I'm fine with just about any level of superpowers, but whatever the levels are in the setting itself, I want Sera to be in the the top ranks of them.
Does that make sense?