That, of course, brings a whole heap of baggage. Is he a fugitive, an ambassador, a tourist, a student, an invalid to whom Earth is an easier environment? What are diplomatic relations with his species? Do they understand the concept? Are there enough of them left to make relations a concept? Are they aliens from another planet, fae from another dimension, mole men from the center of the earth?
All of those affect a story possibly more than any other origin, because they would affect social structure even before you threw in the superpowers. (And if you want "alien in origin" to be a metaorigin, it's going to be a BIG factor. Especially if they can't interbreed with humans.)