Sekai Saikyou no Kouei ~Meikyuukoku no Shinjin Tansakusha~

Workaholic assistant Atobe Arihito fell asleep in his company's bus that was traveling for a vacation. When he awoke he learned he had died due to the bus getting into an accident, and that he had reincarnated into a world of reincarnators - to the Labyrinth Country. To his surprise he was discovered by his slave driving manager, Igarashi Kyouka, who further explains their role in this world.