Yasei no Last Boss ga Arawareta!

Ruphas Mafahl, the black-winged overlord and leader of the Twelves Stars of Heaven, has been vanquished.
A man wakes up in the body of the Exgate game character Ruphas, two hundred years after her defeat at the hands of the seven heroes. The game world of Exgate he knew is no longer ruled by humans—and it is no longer just a game. Exgate is a world of its own where the characters think, feel, and live just like he does. Ruphas journeys through Exgate, looking for the long-disbanded Twelve Stars of Heaven.
Ruphas is without country, army, or allies. A question remains: what’s the real reason an ordinary man was reincarnated into Exgate as Ruphas?