Kyuuseishu ≪Messiah≫: Isekai wo Sukutta Moto Yuusha ga Mamono no Afureru Genjitsu Sekai wo Musou Suru

Summoned to another world as a Messiah, the former hero Takeru Yamato was deemed too dangerous because of his overwhelming power and ultimately executed. After his execution, Takeru awakens in Japan, the world he had lived in before being summoned, now as a high school student named Takeru Kusanagi. However, the city is overrun by monsters that emerge from mysterious Gates, and individuals known as Hunters fight them using magic. Determined to conceal his powers and live a quiet school life, Takeru tries to keep a low profile, but one trouble after another finds its way to him!

(Source: MANGA MILLION)