Name's Demon Layer. Visit Lilian (you can find her in the Town's church) and:
- Interact with her a bit
- Obtain the skill "Holy Headpat" (you need to talk about combat with her)
- Have at least 6 points in Power, Allure and Technique each.
Once you satisfy all these conditions, the next time you pay her a visit should trigger a quiz, answer correctly and Demon Layer will be yours.
Because I have all the Holy hadpat requirements and status levels but when I talk to Lily there is no option to talk about combat and since I haven't played in a while I don't remember if I ever had this conversation with her. I as it has the chance to come out later this year end of April and beginning of May the new update, I will start from scratch, I hope to conquer all the girls again.
Uhhh word of advice? Don't use any holy attacks against Sophia. It actually hurts her and you instantly lose (she's not the strongest arch-succubus for nothing). Demon layer isn't going to beat her.
I pumped all the seduction perks and spammed enamor with about 2k allure and 6 SP. Assuming you can dodge/power through all her attacks and have teleport to escape grapples (and willpower to keep from being locked in a perma loop) the fight shouldn't be too hard.
Alternatively, do what I did on my first character and enjoy playing the game and the loss scenes enough that you're level 400+ and just use your 100 intelligence magic on her until you win despite it being resisted...