You worked with Xiaobo, the reason why Nathan got his job as a bodyguard in the first place but he got soft over time, making him weak not being able to protect P3-NG.. he felt guilty.. It was his fault for not hearing him out.. more likely Breaking his promise to see him again.

The story just begins

Xiaobo just came back entering the shabby basement that you called ‘home’ with the crabby put together P3-NG (from Nathan trying to put him back together) before just Setting him down before he walked towards your unconscious body that was sleeping on an air mattress before placing his foot on you shaking you ever so slightly

“Wake up idiot, and put him back together.” Xiaobo said not caring about being nice.