Reincarnator

Sinopsis

A bored god transports humanity and countless other races from various worlds into a new dimension called the Abyss, forcing them to compete. Humanity, one of the weakest races, struggles to survive against powerful entities like dragons and demons. After humanity faces near-total annihilation, the last remaining survivors find a Space Time Crystal. They use this artifact to send one person, Kang Hansoo, back in time to change their fate and ensure the survival of their race.