Three years ago, Serizawa was troubled with about his psychic powers. One day, he was visited by the boss, Suzuki Toichiro. Serizawa ends up trusting him since he's the first person to understand what he's going through. But Mob then brings up the fact that Serizawa is being used and tells him, "I'll be your friend." Hearing Mob say that, Serizawa... 

Meanwhile, after defeating Sho, the boss starts gathering up the energy he was sharing with his followers and turns into an energy monster.
So be it. It's not like I ever truly 
counted on others to begin with.
فليكن إذاً. فأنا لم أعتمد على الآخرين من الأساس
Egal. Auf andere habe ich mich
sowieso nie verlassen.
No importa.
No importa.
Ma foi, je ne compte sur personne
depuis le début.
Così sia, allora. Tanto non ho comunque 
mai fatto affidamento sugli altri.
Que seja, eu não estava
mesmo contando com ninguém.
Ну да ладно... Я с самого начала
не рассчитывал на других.