Golden_Slime
honestly your character is weak in spirit for a harem, especially in the FATE world , one Rin will split him. Change the plot where he does not want any harems and is quite pleased with the fact that he made himself an ideal wife on his own, but after going to Tokyo to just watch the war and throw a couple of stones into the plot purely for the sake of entertainment, he stumbled upon Manaka. She fell in love with him, and he, trying to get rid of her, told her that nothing would come of them because he wanted a harem. Then he accepts her, at the same time Manaka gets girls behind his back for his harem, along the way finding out which girls he likes