Trafford
Good start just some ideas but Along with grayfia he should marry venelana (she’s just as hot and original wife), maybe use prestige for a political marriage to her and also marry grayfia by merging with Lucifer house to carry on both bloodlines of Lucifer via grayfia and gremory+bael bloodline (destruction) via venelanna, so that sirzech can be born since he’d be a great ally to have as a powerful son plus whatever kids he has with grayfia.