Isekai Kaeri no Moto Yuusha desuga, Death Game ni Makikomaremashita

Synopsis:

He was carrying on with a serene life as any typical high schooler would, until one day he and his schoolmates were unexpectedly brought to uninhabited island. “I’ll have you kill each other until there’s only one of you remaining.” Hearing these words from the man peculiarly wearing a tactical uniform, his colleagues overreacted. Indeed, he was setting up the stage for a demise game. One in which the powerful ate the weak. The frail would pass on without benevolence and just the solid would taste triumph. This was the strategy. In any case, they were ignorant that the legend who was hailed as the most grounded had as of late gotten back from a different universe. By the time the game started, the people who planned it were already out of lick because the expectations they had for the death game, which had worked so hard to set up, would be unintentionally crushed in front of them.