KasiCair
So Serafall is going to be in the harem. Grayfia however is most likely not a candidate - first her relationship with Sirzech seems to be fibe and her relationship with Serafall awful. True in his Naruto fanfic there were also rivalries between his harem members but that Mc didn't cuckold a character who is morally good (there was also Narcissa in the HP fic). I bet there will be no devils in his harem who have either a peerage or belong to a peerage of a morally good character. My knowledge of DXD is quite bad so I don't know any female devil who could fulfill those criteria. (only this halfdevil with a gear who also has the sickness) Stray devils or orpressed peerage members could possibly be fair game and with his gear he could definitely find a way to extract the evil pieces (im thinking of Kuroka there). There are a few other OP nondevil characters who could also be good candidates. There are quite a few mutants, heroes and villains on the marvel side who I won't bother to name. (I just hope for Emma Frost, Rogue, Jean and/or Scarlett Witch Emma especially since he has his own pieces and Emma is the white Queen) On the HP side I could only imagine either Fleur or Tonks. Apropos maybe Tonks is a witch AND a mutant... Food for thought!