Official artwork of Aritsuki (Source)
Existence (有り), Ant (蟻)
Unknown, possibly a teenager
Aritsuki has thick, chest-length blonde hair and teal-blue eyes. She wears a pink shirt with white frilling at the bottom and a white ribbon around the neck. She also wears a brown skirt, along with gray socks and grey shoes.
Not much is known of Aritsuki's personality as her part of the game is still a work-in-progress. The general lack of colour in her nexus and dream world may suggest she has a bleak/dark mindset.
Little is known about Aritsuki's past. She is stuck in a creepy monochrome room.