No. I also opposed his theory outwardly, and even with the information cleared up regarding that male's size in dragon form, I didn't think he was correct in the slightest.

[ In fact, with Akira naming names, Caius doubted it was Corrin at all. Even Hiyori looked even more suspicious. ]

I never spoke to either of them, however based upon their attitudes, Niles appeared more the type to use subterfuge and hide his guilt than Corrin. If anything, I thought it'd be more likely Corrin may take the blame for Niles' crime -- and he did give an attempt at the last stretch to do so.

Corrin seemed to be generally all around much gentler than Niles was, and appeared to be the type to sacrifice himself for those he cared about. Niles, however, even mentioned that he 'couldn't trust him' and that appeared to me as if he were attempting to sacrifice Corrin willingly so he could escape suspicion.

[ And that didn't sit right with him, but honestly, for him it was more the hint that did him in. Niles' actions after that just helped it along. ]