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.
This is my true trump card 
that no one knew about.
هذه ورقتي الرّابحة الحقيقيّة التي 
لم يعرفها أحد
Das ist meine wahre Trumpfkarte,
von der niemand sonst weiß.
Este es el as bajo la manga
que todos desconocen.
Este es el as bajo la manga
que todos desconocen.
C’est ma véritable carte maîtresse
dont personne n’a connaissance.
Questa è la mia vera arma segreta, 
ciò di cui nessuno era a conoscenza.
Esta é a minha verdadeira carta 
na manga que ninguém sabia.
Это мой истинный козырь,
о котором никто не знает.