im a former hero returning from another world but i was involved in a death game

a former hero returning from another world gets involved in a death game. ise kaito departs for a school trip with his classmates. he enjoyed his daily life as an ordinary high school student, but suddenly he was caught up on the stage of a death game where a man in military uniform ruled the place. the weak will die, the strong will be the winner … but they were unaware. that one of the students is the former strongest hero, who returned from another world.