SSS-Rank Dungeon de Knife Ippon Tewatasare Tsuihou Sareta Shiro Madoushi - Yggdrasil no Noroi ni Yori Jakuten de Aru Maryoku Fusoku wo Kokufukushi Se…

[MangaDex]

 

[Alzu]

I remember this. Wonder if he regrets being the bog standard 'let everything under the bridge' protag.