Silmeria Valkyrie is the youngest of the three valkyrie sisters, the goddess of the future.
Silmeria is the kindest of the three Valkyrie sisters. She is warm towards Alicia, and also possesses great knowledge, like the other two. However, she is also a fierce warrior, and will not hesitate to fight an opponent. She is also the least loyal to Odin of all the Valkyries, as it did not take much for her to rebel, compared to Hrist having to see the world nearly destroyed before she went against Odin's wishes. Her greatest and most loyal ally is the vampire Brahms, the Lord of the Undead, who also strongly opposes Odin.
Her kind but rebellious nature, as well as her interactions with Hrist, are a classic depiction of youngest-born children.
While it is not officialy stated, Lenneth being described as the Valkyrie's primary ego and Hrist as the secondary ego, suggests that Silmeria is the id. This fits her more emotional personality.