[Harlan frowns. That's... hm. That's not what he was getting at, for starters, but more than that, this sister with the rumor ability sounds more and more terrifying every time Klaus brings her up. Surely she's grown some restraint by now—or, maybe not, given that her power sounds much more potent than Harlan's magic. If he'd have been able to charm others that easily from such a young age, he's not sure that he would've ever learned to rein himself in. He'd been a much more dangerous person to know.

So either there's a sizeable difference between Klaus' sister and a mother twisting up her child's mind, or there isn't, and he's not sure which is worse. Whatever the answer, Klaus is normalized to all of it, so much so that he doesn't bat an eye at Harlan's admission. Is that why he's unbothered by Harlan being a serial killer, too?

He decides to keep all of this to himself for the time being, though. Reacting with open disgust to the family member that Klaus isn't putting on blast right now wouldn't help the situation.]

I meant practicing your skills is worth it in the end, even if you're forced into it. I don't know if you'd ever be able to make the ghosts go away, but more control can't hurt. At least you'd know what you were working with.