Here are the names of the king's waifus:

First queen: Beatrice Aligieri Spero (the one shown in this current arc)

Second queen: Cheon So-yeon (not yet introduced in the manhwa)

Third queen: Han Hari (the redhead hunter girl who follows Leon around. She gets a power up and also becomes a priestess)

He has children with each of them. Last chapter of the novel ends with Leon and Hari cuddling in bed, then the other queens enter with the children.

Oh, and one of the reasons why he has three queens is because one can't take his nigh godlike stamina alone and needs reinforcements XD