Audino is Tsumugi's sixth Pokemon she owns and is also her first Pokemon who has the capability to Mega Evolve, She made her debut in Sword Heart Online!, she is shown to be quite the nurse to the Light Music Club according to Tsumugi.
In the same episode, she is very kindhearted to her trainer's feelings and learning to Mega Evolve as well, which occurred with Tsumugi's heart connected with Audino as one which made it mega evolve.
On top of Asuna, Silica, Leafa, Kirito and Yui-MCHP001 all witnessing Audino mega evolve. They decided they all want to catch a Pokemon of their own, and Mitsuki and Tsumugi all helped them do that, Azusa helped Yui-MCHP001 and Leafa, Tsumugi helped Silica and Asuna, and Mitsuki helped Kirito catch something that fits him.
She is often used for treatment to help all of After-school Teatime's Pokemon and nurse them to health and mega evolves to use her Heal Pulse to make them better and recover their health in the process.
In What's In a Nickname?, she was officially nicknamed Autumn by Tsumugi because she briefly mentioned she caught her in autumn. She even nicknamed the other Pokemon she has.
Autumn's known moves are: Draining Kiss, Heal Pulse, Dazzling Gleam and Flamethrower, and her ability is Regenerator. As Mega Audino, her ability is Healer.