Neiro is a central character in the anime Kaiba. She is a skilled martial artist and a high-ranking member of the anti-government organization Issoudan. Her missions frequently involve stealth and the use of explosives, and she is also a capable pilot. She has medium orange hair styled in two horizontal pigtails and brown eyes. Her outfit consists of a scarlet bodysuit with white gauntlets, boots, a helmet, and large pumpkin-shaped shorts that house two long, retractable metal legs, granting her enhanced speed and agility when deployed.

Neiro grew up alongside Popo, a charismatic but manipulative leader within the Issoudan, and has been involved with the organization for a very long time. She is largely under Popo’s control, and he has convinced her that if she ever gets into trouble, she has no other place to return to. Her memories have been tampered with, obscuring her true past and feelings. Cheki, an old friend, describes Neiro as normally a very loving and caring individual, but she appears quiet and hardworking under the influence of her conditioned loyalty.

Neiro shares an unknown but deep connection with the amnesiac protagonist Kaiba, whose locket contains a blurred photo of a woman who is later revealed to be Neiro. In events occurring just prior to the first episode, Neiro meets Kaiba and falls in love with him. After he leaves, she is sent to his palace to kill him. Instead, the two escape together and fall through the clouds, a journey that erases memories. Kaiba manages to preserve her memories, but she ultimately falls back into Popo’s hands. Her struggle with manipulated memories and her evolving convictions form a core part of the story, as she gradually works to reclaim her own history and break free from psychological conditioning. Her arc is intertwined with Kaiba’s quest for identity and the broader conflict over memory trafficking in their world.