Kyuuseishu MESHIA~Isekai wo sukutta moto yuusha ga mamono no afureru genjitsu sekai wo musou suru~
The "former" savior, Takeru Yamato, was summoned to another world and executed because of his strength. When he wakes up, he finds himself in Japan, where he spent time before being summoned. However, in the city, demons appearing from "gates" rampage, and those called hunters fight using magic. Returning from another world, Takeru decides to hide his powers and live, but...
Web Novel Raw - https://kakuyomu.jp/works/16817330647537169695
Messiah: Isekai wo Sukutta Motoyuusha ga Mamono no Afureru Genjitsu Sekai wo Musou suru, 救世主≪メシア≫～異世界を救った元勇者が魔物のあふれる現実世界を無双する～, The Savior <<Messiah>> ~The former hero who saved another world beats the real world full of monsters~