[quote=@The Fated Fallen]
So surely he would use his own birth name in his head, except he would tell everyone his nickname 'The Red'
[/quote]

Yes and no, he lives by what people think of him (or in reality, they think of him what he lives by). To his concern, he is the one and only [i]Red[/i] anything, but in the long run it is just a name. Even his surname is assumed, with the only true name he has being Asadan, which has deeper meaning to him and that it is more private.