does any side have access to weapons?
I guess I'll go in assuming they both don't have weapons, and assuming if Assefa is allowed to transform.
The thing is, Violet is used to taking on physically strong humans (usually even when they're in small groups), even when unarmed.
I dunno how her strength will face up against a lion, especially a lion superior to normal ones. In human form, Berber won't beat Violet unless he can deliver a well-placed blow, but in his transformed state, he's more of a match for Violet, theoretically. However, let's assume Violet is in bloodlust mode (because she's not winning with a pacifist mind state)....Violet's punches would be obviously stronger than even the most athletic of humans (here's the calc:
https://vsbattles.fandom.com/wiki/U...k_Potency#Damage_output_of_Violet.27s_punches).
Because I rather not have the pointless "speed equalized" factor here, I'll talk about the speeds. From what I see on Assefa Berber's profile, his speed is Subsonic, but only when he's in Mngwa form. Violet has regularly Superhuman speed, but her reaction are Subsonic+ in terms of combat speed and reactions.
As for Assefa's regen, it seems to be only effective for skin-deep wounds, as bones take a significant amount of time to heal, even if it can heal faster than in normal cats. Violet will likely not be seeking to inflict superficial wounds at all...more likely, she'll be trying to break bones.
Violet, unfortunately, has mostly normal human weaknesses, though she has a high tolerance to pain. She will likely use her admantium prosthetic hands to act as a shield if needed. Assefa, on the other hand, can also sustain a lot of damage, even in human form. His advantage is having his Mngwa coat offering superior protection against penetrating attacks (though Violet, like I mentioned before, is probably aiming to break bones more than inflict superficial wounds).
With these details being said, I could give it to Assefa. Why I don't think he's better than Violet in terms of military combat, due to his ability to transform into something stronger than even most superhumans, he has way too much of an advantage due to being capable of turning into a wild beast far stronger and bigger than her.
With that being said, Violet does have a feasible chance, but it depends on whether or not Assefa is gonna use his Mngwa transformation or not.
