Will work more on this when I have time but some points you will need to know:

-he can't speak Korean very well, so his speech will be broken and he won't understand a lot, but he is very observant which will work in his favor

-he does have martial arts training, with makes him very strong and flexible

-unfortunately he is easily intimidated, so controlling him will be easy unless you show him a weakness. 

-He's not a (unless you talk to me before and you want him to be) 

- he has a very submissive personality unless you try to hurt one of his friends or loved ones