Complex sentence: Karma then brutally beat the teacher, leading to his transfer to 3-E. Because of this experience, Karma originally distrusts Koro-sensei, but Karma begins to accept him after realizing Koro-sensei is unlike the other treacherous teachers at the school.
Split into simpler sentences: Karma then brutally beat the teacher, leading to his transfer to 3-E. Because of this experience, Karma originally distrusts Koro-sensei. But Karma begins to accept him after realizing Koro-sensei is unlike the other treacherous teachers at the school.