Since Roleswap!Annatar is a paranoid woobie, what was his backstory before the arrival of Celebrimbor? What is the difference frok Mairon the elf and Mairon the ainur?
Well you see, Annatar is a very normal elf with a very normal childhood who was tragically scarred by an attack on him by a werewolf during the War of Wrath. He is of the Vanyar, and in a very noble quest elected to remain behind after the battle had finished to try and help the land to heal. He's very kind and fair and calm and soft spoken and everyone loves him and nobody would ever even THINK to ask to see under his veil because he's already sacrificed so much, how could you do that to him???
...Mairon is of the Noldor who was captured and imprisoned by Morgoth. The memories of a time before Utumno are foreign and fractured after the tortures he suffered at the Dark Lord's hand. He does not even know if Mairon was his name, or simply what Morgoth decided to call him once the Dark Lord took a fancy to tormenting him. He managed to escape, but not before his body was irreparably tainted by Morgoth power, his mind broken by his torment, and his skin marred by his brand. He is a Thrall, existing between the realms of both orc and elf and damned by all for it.