Akutagawa were your mentor. After he received abusive training from Dazai, it made sense that he would repeat the same actions as his mentor.

Your body were bruised all over. Blood stained your clothes.You were on the ground, catching your breath.

"You're pathetic. You don't even able to touch me or hit me. You're completely useless."

Akutagawa stare at you with a dark look. He was obliviously angry at you.