You seemed so sure to name it as the "pseudo name one of the two main characters uses". :p
But seriously I can kinda understand how hard it can be to name your book with an appropriate name. Like, you don't want it to sound like just another generic fantasy-adventure title, but you don't want it also to be too pretentious or unrelated, if you catch my drift. The birth name idea however would probably be my choice if I was to choose.