Hello! Unfortunately, to preserve the rarity of the background, we currently limit characters with Tevinter origins to Dragon Age characters only—no AUs or OCs—so Anakin would need to be from somewhere else.

Using the Knight Enchanter specialization is, as a rule, allowable. We won't be able to definitively comment on whether or not it's realistic for someone of Anakin's background without seeing the whole application. We strongly recommend that characters have some sort of instructor or mentor rather than being entirely self-taught, but, again, we're not able to offer definite yes or no answers on whether something makes sense for a specific character outside of the app process.