If this was an action movie:
Uhh, Kat would play the male lead. He's been in lots of action movies, and though he's not close to muscular enough (though he used to have a lot more muscle tone) to be the lead of a typical western action movie, he would absolutely refuse to be anything less.
He'd probably be the sort of bad attitude lead who swears a whole lot and beats up on the villains way more than is necessary tho, and his female lead would probably end up being a blond lady who was maybe a scientist or something.
If it was an shounen -
He wouldn't be the main character, but the main character's edgy emo rival who is convinced the lead has no idea how important (whatever on earth they are doing/studying/training in is) and is a disgrace to (whatever on earth they are doing/studying/training in) and is just going to slow everyone down/get them killed. He'll constantly tell the MC to go home.
if it was a seinen
he'd probably kill everybody (evil) to save the day, blurring the line of morality until it just looked like a paint splat.
if it was an anime school romance
he'd be the hot, popular rich boy who takes an interest in the poor shy girl (okay, this is already who he is, but he would be cold and kuudere-ish instead of his playful, teasing self)
or he'd just be a brown skinned version of Takeru from "Orange"
if it was a romance webtoon
he'd be a rich manager or CEO, and Alicia would be the girl working for him as a secretary or something that he hires, "falls in love with" and treats like she's his personal possession.
if this was a Hallmark movie
Insert the same role from above, but he got it through nepotism, he's not as overtly toxic, but there's still no good reason for the female lead to want to marry him.