Board Thread:Editor Board/@comment-26391060-20131113175757/@comment-6697950-20131113211110

It's neither confirmed nor denied that ALO supports kanji, but it does seem that all characters known so far use names that are katakanized in the novel, most of which are actually written in alphanumeric. The only questionable instance is Kirito's name, as the novel does mention him using the kana form of his name, but this was never again mentioned anywhere in the novel, so it's hard to say if it's true, or whether the translator made a mistake or Reki just changed his mind to simplify things.

Anyway, there's no known instance of a name being written in kanji in ALO, thus I doubt that "Angel" is this angel's real name. I wouldn't be surprised if it turned out to be Angelica though...