>>38558566>>38558578>>38558592>>38558600>>38558609>>38560151I happen to be an expert on this subject.
It's Eliza from the ROMhacks Pokemon Victory Fire / Resolute / Mega Power, all made by the same author.
She works with the villainous team in Victory Fire and defects after the events of that game to work with the protagonist in Resolute and Mega Power, although in both games she does little more than just talk and offer free healing at a couple points - and otherwise works as a rival battle where she sends out herself as her own ace. As expected, being a Zoroark she can't take a hit at all and doesn't have Illusion - and since each game doesn't have bullshit powerspikes you usually just one-shot her each time.
In the very end of Resolute's postgame you are able to recruit her by giving her a sword you found as a secret item in Mt. Silver, which is a bit weird since now she continues to exist in the game's world despite now being 1 of your Pokemon.
You then discover she is Dark/Fighting, has 150 Attack in addition to the rest of Zoroark's normal stat spread and has
Huge Power as the Ability.