I don't even think the goblins would be involved in this war, and the vamps are unlikely to join either, because the Tower doesn't mind the Vamps and Goths and what not. Hence why you can take your little imp in there. Those factions aside, I agree with the rest being said here.
If the Temple of Love and the Mistress of the Dark Arts were to fight, then the MC definitely would need to fight for both. Since he obviously can't, he needs to side with one over the other.
So, push comes to pull and I have to chose, so I would pick the temple of love. It's a warm and nice place, with children playing everywhere and 4 supportive, loving women who want nothing but sex from you. Why would I ever pick the cold and distant lady, who is constantly not in the mood for sex, is involved with very dubious dark arts, practices human sacrifices and quite frankly never done anything. She is also very bossy and doesn't seem to care what the MC does very much. Fuck the monsters in the basement? Pf, whatever. Fuck your own daughter? Eh, ok. Not come back for 6 weeks straight? K. Sleeping in the same bed? Ehhh... only under special circumstances. How dares he go to bed if I am not in it or before we had 4 children together!
She is hot, and the daughter is hot, and the imp is .... a useful fleshlight, but if I can't have both, I would absolutely take the light and not the darkness. Good vibes only!