Harem as fuck. Classical plot, bit cliché but ok. Bullied by his half siblings, Mc remember his past life. This new world is similar to a VRMMO he used to play back in Japan. Realizing he can use his magic has in the game, he set off for an adventure far from his noble family, together with his trusted maid, a (strong) half vampire.
Boundary Labyrinth and the Foreign Magician