Grand Drive Harem Cultivation

His name was Andro Von Wellbing. A boy who was born under the chief maid and chief butler of the Wellbing family, he was sworn to become a butler for the next Heiress of the Wellbing family.
When the family of three was living happily, he was assassinated by an unknown enemy of his father and mother which got him killed at the age of 137. Unknown to him, he was able to take rebirth back to the age of 12. Where he started to find out, the hidden enemy that had been planning to uproot the Wellbing family.
As he continued his search, this time he was accompanied by an unusual system called [Grand Drive Harem Cultivation]. Which makes him choose a different life that he had never imagined to walk on.
Cultivation in the world of Sword and Magic. Our protagonist is gonna walk on the path of the unknown, that no one had heard of in any story.
'Harem is the way to supremacy...'