Ais Wallenstein is a tritagonist in Is It Wrong to Try to Pick Up Girls in a Dungeon? and the main protagonist of Sword Oratoria. She is a first class adventurer and an executive of the Loki Familia. Among the small fraction of first class adventurers, she is considered one of the strongest.
In Japanese version, she is voiced by Oonishi Saori.
In English version, she is voiced by Shelley Calene-Black who also voiced Yuriko Takagi in Highschool of the Dead, Najenda in Akame Ga Kill!, Nobara Yukinokōji in Inu x Boku SS, Luviagelita Edelfelt in Fate/kaleid liner Prisma Illya, Ageha Chono in Wizard Barristers, Medaka Kurokami in Medaka Box, Shimura Otae in Gintama: The Movie, Fujiko Eto in Demon King Daimao, Canaan in Canaan, Cortana in Halo Legends, Hidemi Kinoshita in Btooom!, Ririko Kagome in Rosario + Vampire, Kalifa in One Piece, Zola Axberg in CROSS ANGE Rondo of Angel and Dragon, Emera in Tenchi Muyo! War on Geminar and Mireille Bouquet in Noir.
Ais is considered a very beautiful woman with long golden hair, gold eyes, and a slender body. She usually wears a white and black battlecloth, black arm covers, and long blue boots. She wears her armor over this consisting of a headguard, breastplate, arm guards, hip guards, and knee guards.
When not heading to the dungeon, Ais usually wears a white dress with a blue line and flower patterns along with a blue skirt, white tights, and blue shoes.
Ais is a mostly quiet person who has trouble expressing her feelings through words. Because of this, she is thought to be mysterious; however she is actually mentally young, even visualizing a younger version of herself in certain situations such as when she gave Bell a lap pillow.
Unlike her fellow Loki Familia member Bete, Ais doesn't look down on the weak despite being a First Class Adventurer. She is also believed to be an airhead, namely due to her quiet nature. She is very strong willed, doing everything to reach her goal to become even stronger, even offering to train Bell just so she could try to determine the key to his quick growth. She also tends to react violently whenever someone does anything remotely perverted to her (such as Loki).
Ais exhibits a strong interest in Bell, mainly because of his rabbit like appearance. However, she helps him whenever she can, such as when she immediately moved to rescue him when she heard that he was being attacked by the Minotaur. During the time she trained Bell, Tiona pointed out that she seemed happy, an emotion she had never seen her show before. She interacts with Bell very favorably, such as taking care of Bell on the 18th Floor and accepting his request to dance even though it was her first time.
Ais is unable to swim, as when she was 7 years old, Riveria punished Ais for calling her an "old woman" by tying adamantite to her and throwing her in water, calling it "swimming training". This later became a traumatic experience for her, making her avoid water in general while in the dungeon, and if she has to bathe she tries to stay in areas where her feet reach the bottom.
Ais' goal is to become strong enough to defeat the One Eyed Black Dragon and take back her mother. Because her goal is revenge driven and for her own sake, she considers herself unable to become a hero.
Ais entered the Loki Familia at the age of 7. As a new member she acted as a supporter to other adventurers while training as hard as she could. She reached Level 2 within a year, becoming the fastest person to reach Level 2 at the time until Bell broke that record.
Ais has also fought against Phryne Jamil on three occasions: once when she was a new Level 2, a second time when they encountered each other in the dungeon two years after their first meeting, and a third time when Ais reached Level 5.