For if Billy were to do something as disloyal as that, he knows I’d stop at nothing to see that offense repaid against him.
Have you gone on the character TV Tropes page for Markiplier? I made me realize something interesting. When Darkiplier says "let me in", he doesn't really specify what that entails. "We'll be together forever", "You can never escape", everything he says can be either interpreted in a (twisted) romantic sense or a demonic possession sense. Or both.