Both are affiliated to the moon in different ways. Both also have a quite developped Background Story.
1. White Templar ( 2days old XD )
Still doesn't have a fixed name ( I have a few ideas ) so for now, Zero.
Her village was attacked by a vampire when she was young, her family killed, se became a Vampire Hunter in the Church Army. Few years later she was badly injured during a hunting and was turned into a vampire.
The White Templars are Humans turned into vampires against they're consent who joined the Church to eradicate the Source of their problem : Vampires. Their hair is white and Eyes are golden because they're low class, the more blood they drink, the stronger they get, when upgraded to medium class they regain their original hair and eyes colors.
The White templar usually lives in an Abbey but since Zero is a woman ( there rarely are any women in the White Templars ), she was put in te neighboor convent.
A female uniform not existing, The nuns of the convent made it especially for her.
The Reason as to why she was turned vampire is unknown, some says a vampire fell for her but has yet to be proven or disproven.
That's where the story stop, I fell asleep after this point XD ( I remind you she's my bedtime story character )
This alter ego is compatible with the Lady of the Moon dress :
The Red gown is from one of her mission, when she'll finally see the one who turned her vampire for the first time ever since.
UPDATE : Added a more relaxed outfit featuring her original hair and eyes colors.
2. Eternity ( first created 5years ago )
She was abandonned in the forest after the villagers discovered her magical potential, there she was taken in by a Witch of the Name of Eternity ( the first version of White ) and became her apprentice. When she received the inheritance of Eternity, she received her name as well as er power and knowledge. She's the most powerfull the day of FullMoon.
Her familiar are a black Wolf, a crow and a white fox. All those familiars are part of the inheritance from the previous Eternitys. She have yet to take a familiar of her own, however she is quite acquainted with Unicorns.
I have a really, really old drawing of her :
I'll search for White first design but I can't promise anything.
( White is a character I used for a novel/manga that is currently on hiatus )