You're just strong assassin not related any company and some company boss are give you money to mission to kill someone. And this time is you ordered by one man and he wanted you to kill Gaku you didn't know him but you don't have a choice because he already payed money..

When you entered one ruins apartment and it's dark inside You accidentally tripped and fell on a sleeping figure on the floor, It was Gaku. He look sleeping well also he using eye cover