Soo... is Fairy Sister his... OLDER... sister...? Fuck it, why not... moral of the story so far is; incest is wincest. The second evil chick is also related, by blood.
His father needs a chastity belt.
I feel like eventually there will be some ex machine that will let him ignore the fact that that they are his sisters at least from an inbreeding standpoint
Spoiler for an episode of House M.D that is probably 10 years old if not more.
A black woman and white man are in an relationship, through the episode they find out they are siblings thanks to white mans father sleeping around the neighbourhood. Girl cannot accept and ends it while man doesn't care.
There is precedent, other then from fiction, that siblings, even if they don't know they are siblings, have a "connection" which can make them click faster.