Seinvocc

He's kinda' right. I mean, I don't mind if you leave a lot of your bio details to mystery, but, especially if you want it to be in third person (as that's generally a clean, reliable method of writing bios), you shouldn't just say something like,
"he wok up outsid huocm wit no memeri," or the like. Put some effort into it; think things through. If you really don't want to put a lot of effort into it, at least tie up the essentials. If you say that you're from some other planet, what's the planet called, and in what galaxy, what universe, what dimension-intersection? How did you get here? If your character lacks memory of past events and you're writing a third person bio, what caused the memory loss, and what memories were lost? No, you don't have to give a detailed outline of everything in the character's imaginary life, but don't just use lack of in-character knowledge as a cop-out to any sort of a decent bio. We're not asking for much; a paragraph or two could serve as an acceptable bio, but don't just throw some generic info out and call it good.

Relatedly, if you're the kind whom likes to write an essay out of your character bio, you're allowed to do so, but don't expect me to read it any time soon, so, if there's any sort of relevant info in there, it should be pointed out immediately. I don't care whether you do so by boldfacing and underlining important details that will be noteworthy in battle and such or simply stating a list of important details outside everything else, but, if you want to spend four hours writing a bunch of stuff that most people aren't gonna' bother to read (which is partially because many people whom write long bios do so in unoriginal, boring, and trivial ways), spend another four minutes to outline any stuff that we should care about.