Thread:Taki-Tan/@comment-30202748-20170416202632/@comment-29264888-20170429234454

Well, they originally started off as part of the Soul Eater Fanon.

Yin was a young witch who resided in Death City. Despite the racial discrimination between witches and humans, Yin was an exception to that divide; being an ally of the DWMA and was respected and trusted by the residents of the City. She doesn't make any direct contribution to DWMA's cause, but she does supply DWMA with books of various categories whenever she comes back from her travels. Though one may not see her as much, Yin has the bloodline of Etheria and studied under her grandmother for most of her childhood. Should she ever need to fight, one will find her a formidable opponent.

As for Etheria, she was known as the free-spirited witch. Though there is actually no clue as to what she does, she appears from time to time to check in on Yin. But every time she checks in, she is usually taking Yin to follow her in her random adventures. One day, Etheria could be taking Yin to help her figure out if a certain ghost story is true, and at other times she could be fishing with her at a pier on the other side of the world.

DWMA and the residents of Death City see Etheria as just a friendly witch just like Yin. However, following the rule of "don't judge by the cover," she is a witch who rivals or surpasses the Great Old Ones and the Grand Witches. She has various relations to both sides of humans and witches, but takes no sides. She is only an observer to the trouble of the world.

For everyone else, they all have their own original stories.