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.
Apparently, you still don't 
understand how powerful I am.
يبدو أنّك ما زلتَ لا تفهم حجم قوّتي
Ich scheine dich noch nicht
das Fürchten gelehrt zu haben.
Pareces no comprender
lo alarmante de la situación.
Pareces no comprender
lo alarmante de la situación.
Tu ne comprends pas
à quel point je suis redoutable.
Sembra che tu non abbia
ancora capito quanto sono potente.
Parece que você ainda não 
entende o quão poderoso eu sou.
Никак не поймёшь,
что меня стоит бояться?