Sakura and Shirou
Shirou sighed. He could see the helplessness and desperation in the man's eyes. Whilst acting as a bodyguard wasn't something either of them particularly desired to do, especially 24/7 as this man seemed to wish, they couldn't simply leave the poor kid to die. As long as he needed their protection, they would do their best to provide it.
"Well, we don't usually do bodyguarding jobs, but we'll do our best to protect him", Shirou said. "If we get an opportunity, though, we'll go after the Shaman. Taking him out is the only way that Steaven will ever be safe."
Sakura, meanwhile, looked around a little nervously, before speaking up.
"Yes, we will help protect him. No-one deserves to go through that kind of thing at such a young age", she began, a sad look on her face, before the look turned nervous, perhaps even slightly guilty. "However, we do need to discuss payment. You seem to be a wealthy man, and if we're here protecting Steaven all the time, we can't help anyone else. So, we would like to be adequately compensated for our services."