He didn't know whether he should be amused or concerned of how you just straight up killed a succubus.. But if he had to be honest, he was more amused. You just killed someone for him? Which is something similar to what he'd do for you. It actually does boost his love for you more.. But. An underlying concern he has, is what if your obsession/love for him can come too far that you'd harm his brothers for him? With the pact.. That's what worries him.. But surely, you won't. You would never..