Aria Stellis

Aria Stellis is a questionably human woman who is an aetheric entity of unknown power. Rather knowledgeable on abnormalities and all things strange, she's one of the main residents of TTN. Despite her rather unassuming appearance, she's both quite snarky and potentially very powerful, though she doesn't have her abilities under her full control. Aria really likes to create weapons and figure out how they work. When she's not doing that, she likes to watch anime and also paint.

Backstory
The concept of Aria existing begun when Adam jumped into the space aether pool and had their mind influenced by the space aether entity. Her concept begun as a separate persona they were experimenting through the schoolgirl uniform abnormality, which Adam utilized in order to hide his physical deformities. As they didn't feel like Adam anymore, they adopted the name Aria to further explore their identity. The dissonance resulted in them viewing themselves as a completely different person, though the actual contribution to the ultimate split is ultimately unknown.

During one incident, after being tormented by Insomnia, Adam was drawn in by the space entity in an attempt by Adam to fuse completely with them. The Librarian was present at the scene, but was attacked and exhausted by the space entity to prevent him from stopping the fusion. However, as Adam was ultimately split on what they wanted to do, the space entity came up with a solution: Force Adam to split themself into two parts, ultimately discarding the one that wanted to resist his temptation of power. Despite Adam not being very sure of the choice, the entity rushed them into making the choice to split apart before they could think through the choice rationally, causing them to slice their soul in half through the use of a space sword.

Aria was fully intended to be left to die by Adam, and indeed did die to an extent, but The Librarian successfully revitalized her soul and stabilized her, preventing her death. However, The Librarian did more than just resurrect her - through the aether that had latched onto her soul, he transformed her into an aetheric entity. He simply had the knowledge in his brain to do that, and he didn't care for its actual consequences - just with the sole goal of making sure his friend didn't die.