Nelliel Tu Odelschwanck (Nel) is the former Tercera Espada. She lost her rank after being attacked by Nnoitra Gilga. The attack cracked her mask fragment which caused her reiatsu to leak out and changed her into the form of a child. She lost her memory after that incident and was left in the care of her former fraccion.
Her zanpakutou's name is Gamuza, and it's release command is "proclaim."