[Ren's halfway to taking another drink himself as Henry talks, except he looks very surprised at the notion that he's not interested in dark magic at all and sets it down again, waving a hand.]

Oh, no, the whole immense power of dark magic thing is totally fine with me, I just don't think it's very interesting to make people explode. [Because clearly being fine with dark magic is something that needs to be cleared up.] If I don't have to kill someone, I'd rather not do it...so it'd be fine if I could just defend myself and make someone really regret having decided to fight me in the first place.

[The tone with which he says that is far too cheery compared to the actual words being said, though Ren could be a lot more questionable about the subject if he wanted to.]