By the time you listen to this

Hugging this character:: Go for it, see just how he freezes up with the simple contact.
Kissing this character: Probably best not to.
Flirting with this character: Go ahead and try.
Romance/Sexual Relations: Might be difficult unless your name is Kazuki but anyone is welcome to have feelings for him.
Fighting with this character: Sure, though Soushi isn't extremely physical and will be attacking from a distance
Injuring this character (include limits and severity): Bring it on, he can even lose a limb only to get it back.
Killing this character: Let's talk first.
Using telepathy/mind reading/empathy abilities on this character: Yes, absolutely but fair warning that Soushi has excellent mental shields and his own telepathy/empathy abilities so he can throw it back. Also there is a lot of emotional pain from the loss of his friends and something deep within in his mind that is the equivalent of understanding what nothingness truly is - the sort of nothingness that a person could get lost in.
Healing: He might protest if his own wounds aren't severe should there be other people worse off but otherwise it's fine.
Triggers: Soushi is a surprisingly calm individual and difficult to shake. Going at him through Kazuki Makabe festumkept is an excellent start.
Medical Info: He is physically not human even if he looks like it.
Mental Info: Soushi was once mentally linked to a species that had a hive-mind, one that doesn't communicate in any known language found anywhere on Earth and other versions of space. These creatures known as Festum have killed billions of humans since they came to the planet and their sense of existence is something that is complicated to understand. He spent two and a half years in this collective consciousness and the backlash of trying to comprehend it may be difficult. Also, there are many memories of sharing mental, physical and emotional sensations with multiple people - including a few deaths and lots of extremely painful "wounds". Feel free to ask if your character intends to attempt to delve into Soushi's mind.