Thread Hopping: yes
Teasing/flirting/romance: HELL YEAH...But you might be surprised by how he reacts.
Harming/Maiming/Death: You can hurt him anyway you'd like, but anything drastic like maiming or killing, or really anything that will leave scars should be talked about first.
YOUR POWER AGAINST HIM: He's an android so anything that will only work on flesh or normal humans, probably won't work on Gakupo.
YOUR SKILL AGAINST HIM: He's fast, strong, and skilled in the art of the sword. But you can cut him, out wit him, and maybe you are even better then him. It just depends on how skilled your character is.
Honestly I'm good with most things, just depends on how likely things are as well as the severity of things. If you think something is too severe go over it with me first, and 9 out of 10 I will say "GO FOR IT". If they end up in a battle I just ask you not to god mod over it. What I mean by that is "My character is invincible and all your attacks are ineffective." Now if your character is a god...and invincible, realistically Gakupo isn't going to fight you. Kids not stupid, he'll be going off to get back up, or he'll hold you off until back up comes. He may even save a damsel in distress. But unless their's someone to save, he ain't going to fight anyone he doesn't think he can handle.