Character's name: Mitsuru Kirijo
Are you cool with dealing with Xanxus's complete jackassery and excessive profanity?: Totally. Pretty sure Mitsuru's heard a good few things since she's modern day, even if she might find it disgraceful and rude and everything in between.
Can Xanxus throw things at your character?: I say yes but I'm just horrible like that and you don't have to do it.
Can Xanxus punch your character?: S...ure. But again I'm just horrible like that so you totally don't have to have him do so.
Can Xanxus shoot at/pick a fight with your character?: Like the previous answers |D
How much of an ability does your character have to fight back?: Depends. If she has her Evoker, pretty good damage. Blades (namely rapiers), pretty decent damage. But she would need to be angered/pushed enough to actually fight against another person.
How much damage is Xanxus allowed to do?: Life threatening: possibly a talk it over deal depending on how life threatening it is /o/ Otherwise, cuts and bruises and burns and non-life threatening broken/sprained limbs are all okay.
Anything else?: Not that I can think of |D