My bad about Chapman's ending. I totally didn't remember that at all. But having said that, there is still zero supporting idea to say that Nadir is Chapman. On the other hand, I think there are more hints to say that Chapman is not Nadir.
1. Chapman was said to open a theatre after retiring from armory. But it has never been mentioned that he was a performer himself. To me, I take that sentence as a way to say that he opened a theatre, but did not perform himself. He just provided the stage and place for actors/actresses to perform.
2. Chapman had no reason whatsoever to hide his identity. So it doesn't really make sense for him to wear a mask and be mysterious.
3. Futch, Viki, and Jeane were all involved in Gate Rune War along with Chapman, but there was no indication at all that Nadir knew any of those three from the past.
So in the end, it's of course possible for Chapman to be Nadir. In fact, anyone can be Nadir at this point. But still, no direct evidence that pointed to them at all. My conclusion is still the same, that Nadir is Nadir.
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