Perytons also have aspect of unusual shadow! Depending on the interpretation, their shadow is either human, becomes human after peryton eats a human, only changes to their own once peryton eats a human or reflects last meal they have eaten! So Alastor being a peryton also would explain his shadow, or at least make it thematically fit
Yes exactly!!!! It's so fitting for Alastor, I know it's not canon but it's canon in my heart.
I'm also playing around with the idea of Alastor being distantly related to Furtur Ars Goetia, a who is literally just a peryton himself. Fun HC for anyone who wants to think more on peryton Alastor, pspspsps come get your crumbs!