Archangel Gabriel following his brother to Earth, distraught at what happened in Heaven, wanting to bring Lucifer home and repair the rift (that can never be healed, really, but we’ll just patch the pieces together and no one has to know if they don’t look too close).
Archangel Gabriel finding his brother stalking the Earth, exercising his newfound trick - torturing souls and creating demons - and Lucifer is so new to this idea of freedom and choice that he tries everything (he hasn’t learned regret and will do his best never to).
Brother Gabriel, begging Lucifer to come back home, to be his older brother again, protector and playmate, but Lucifer just smiles (the Morningstar shines and it is sickening).
Prisoner Gabriel, experiencing physical pain for the first time as Lucifer pokes and prods and slices and cuts and explores, crying out for his Father, his other brothers (they hear, but no one comes, and that is worse than anything Gabriel has experienced in the entirety of his existence - abandonment).
Broken Gabriel, no longer looking to Heaven, fleeing his brother and his experimentation, horrified at what he has become, acutely aware of how he is irrevocably changed, with a niggling thought in his brain that maybe he has been set free (a ship adrift in the ocean, loose and unmoored).
Demon Gabriel, stretching a hand out against a human, against the very thing he swore to love, against the Father who let Lucifer do this to him (Gabriel laughs and something in Heaven breaks at the sound).
Demon Gabriel standing against Raphael as Michael casts Lucifer into the cage, fleeing into Hell when his brother is lost, learning to hate a little more each day (gold veneer and deception hide the black and rage in his eyes).
Archdemon Gabriel ruling Hell and commanding its battalions, exploiting the weaknesses of his brothers, systematically picking off the garrisons left behind as Earth is abandoned (a neutral middle realm, left as naked and wanting as the archangel Gabriel once had been).
Archdemon Gabriel, all beauty and tragedy and terrible power as he leaves Hell to itself and roams the Earth, dispensing judgment that had once been his Father’s, but is now merely his own (Heaven waits for instruction, silent, as God weeps).