Inner Fire

"Hero slaughters the monster and also excite the princess enough to fall in love with him" - this system in fact operates in the world of "Journey Time" too even though hero is not even a guy yet hot looking Fionna, the princess is in fact the Princess of Flame who can melt some monstrous asses by herself ... and also even the monster is a tentacled creature who is not in fact slaughtered yet joins the 'falling-in-love" part ultimately- the really happy end!