WORST GAIDEN: ZETTON-SENSEI

After years of studying, Hanazawa Saburou, AKA Suzuran's legendary Zetton, has finally become a high school teacher. But on his first day at work, the principal tells him he was actually hired not to teach, but to make the students of his homeroom class drop out of school?! — Description from AniList community (anilist.co).