Undine's Friend

In a confrontation with Undine, Deneve notices Undine's second sword has a different symbol than Undine's. Deneve guesses that a friend of Undine died, possibly because Undine at the time was too weak to protect her. So Undine took her sword in her friend's memory. Her name and rank are unknown.

Anime and Manga differences

 * In an Anime flashback, an earlier untransformed, frail Undine stands over the body of her fallen friend holding her friend's sword.