Was the apparition Shion saw in his flashbacks Izanagi?
Prior to awakening, Izanagi was a gold humanoid specter (we see this at the end of the OVA when Yin talks to izanagi). So as izanagi was not yet awakened, if Shion saw a gold specter, he was seeing Izanagi. But, if he saw himself, he was seeing Shion.

I could not find this scene in the anime, but Izanagi only awakens at the end of the series, so up until then Izanagi would be a gold specter.

EDIT: The scene is at 09:20 in episode 11. That is not Shion or Izanagi; rather, it is Yin's evolved specter. I do not know the relevance of that scene, but Yin may have been Kirsi at that time and not yet a doll, so Shion may have been seeing the future.