Yui

Yui began her existence as an AI counseling system within Sword Art Online, designed to support players' psychological well-being—until fate led her to become the cherished virtual daughter of Kirito and Asuna. In Sword Art Online II, she takes on the form of a nimble Navigation Pixie in ALfheim Online, leveraging her extraordinary data processing and search capabilities to investigate the deadly mystery of Death Gun in the Phantom Bullet arc, and to provide vital support to her allies throughout the Mother's Rosario arc. Her indispensable contributions make her the backbone of the entire team.