Leo - Art's genetic template, who he refers to as his older brother. Art deeply unsettles him. It is unclear if he's doing this on purpose.
Artemis Lind - Another NEK0. Art's creator had based him on what he had heard about Artemis from his master. Art sees him as a curiosity due to how different he is from that impression. After the dissolution of the company, he now treats Artemis as his master.
Ozzy Fowler - A demon who's attention Art caught whilst attending the local prom. Art enjoys his company, though whether Ozzy can truly befriend him remains to be seen.
Kyo Tatsuzaki - Scientist responsible for fixing several of the genetic issues inherent to other NEK0. Art is a scientific curiosity to her, and he greatly enjoys assisting Kyo in her endeavours.
Maple - A fellow company NEK0. Art admires her competence and her adaptability, though the way she so quickly seems to be moving on from the company upsets him.
Murasaki - A fellow company NEK0. Art has a paternalistic attitude towards him. He wants Murasaki to flourish, but only in the way he deems the best for him.
Jasper Lee - Due to a miscommunication, Art is under the impression Jasper is a NEK0. Jasper is under the impression Art is a bakeneko. They somehow have not figured out the truth over multiple conversations. No one has explained this to either of them yet.