User blog comment:IamJakuhoRaikoben/Chapter 373: Life or Death?, Review./@comment-5303512-20140301213856/@comment-7418318-20140302193847

I don't believe it either and meant it as a joke, though his different bearing can easily be explained.

If anyone, including the other Raven Tail members, would have found out his true identity, it might raised a few eyebrows which wouldn't have fit into Tartarus' plans, so he made sure to act contrary to his true nature.