i've seen a lot people mention how phainon's wings are different colours, with the golden one representing the chrysos heir/hero phainon and the other one representing flame reaver. here's a picture for reference:
from this image, we can see that his right wing (phainon's right. i am actually terrible at lefts and rights) is the lighter one. this is the wing that zephyro cuts off in the animated short:
(also: that shot of phainon falling after losing his arm is so reminiscent of nanook's severed arms. it's a great detail)
phainon loses his lighter wing first, which symbolizes the first part of his character arc: the loss of his idealism. he realizes that being the deliverer is nothing like the heroic fantasies of his youth, and that there is a steep price to pay for "saving the world". this mindset culminates in khaslana (in the first timeline) discarding "the hero within" so that he can press on as the flame reaver. it's also fitting that he loses this wing in a fight; at this point in his life, most of the grief and anger he feels arises from external pressure rather than self-sacrifice. he sees destruction as a force outside himself, something that he must fight and eradicate.
at the end of this sequence, we see an injured phainon struggling to stand, left with only his dark wing.
this is the flame reaver left at the end of the cycles: unbalanced and barely conscious, resting atop a pile of corpses.
AND THEN HE CUTS HIS OWN WING OFF.
i've seen people question why he did this, and i'm not well-educated enough to answer that from a physics standpoint. but from a symbolic standpoint, i think this is phainon letting go.
after 33,550,336 cycles, phainon finally sees another way out. he realizes that he doesn't have to be amphoreus' sole saviour; in fact, he realizes that he's incapable of it. this moment represents him letting go of that "obsession with deliverance". he cuts off his wing, which was a physical symbol of his desire to rise and become the sun. and with it gone, there is almost nothing left of the person we once knew as phainon.
cyrene once said that the deliverer card represents absolute harmony. which is ironic, because flame reaver and chrysos heir phainon have always been at odds. but here, at the end of everything, he's lost (or discarded) both those identities. and i'd like to think that that is also a form of harmony, or at least a form of peace. i'd like to think that phainon is still a deliverer in some unexpected way. i have to cope with the events of amphoreus somehow, right?