Ako is a short, petite girl with big, sharp crimson eyes. She has long light purple hair worn in curled pigtails with matching forelocks and straightened bangs. She is also shown with a fanged tooth frequently in the anime and card art.
Her casual attire borders on the mix between punk and gothic design with a cute flair.
Ako is shown to have chuunibyou tendencies and illusions of grandeur and magical powers. Rinko suspects this is the result of her playing online games frequently. She enjoys playing the role while keeping a realistic mentality. However, she tends to sometimes stumble on her words when she's not sure what to say while doing this.
Ako is a cheerful and noisy girl. Although she's only two years younger than the other Roselia members, Ako is treated like the kid sister by the other characters due to her childlike appearance and personality. She is also a very hardworking and passionate drummer, though she may be bad at schoolwork.
Ako often wonders how she can be a "cooler" person, and sometimes feels inadequate compared to her other bandmates; however, as the story goes on, she becomes more confident and both Yukina and Sayo, who initially scoffed or ignored her ideas sometimes, also come to understand her more and get used to her chuunibyou side.
A list of characters Ako interacts with in the game (during Lives and in the dialogues at the end of every game).
Udagawa (宇田川): U (宇) means "whole world" or "universe", Da (田) means "paddy" or "field" and Gawa (川) means "river".
Ako (あこ), depending on the kanji writing, possible meanings may include "my child" or "harmonious heart".
- Ako is a member of her school's dance club together with Lisa.
- She is the shortest Roselia member.
- She plays the Necromancer class in Neo Fantasy Online, the online game she plays with Rinko.
- She admits to being bad at reading sheet music.
- Ako loves horror stories and haunted houses.
- According to one theory, though it is confirmed neither by Bushiroad nor CraftEgg, she shares the same eye color and hair color as Tomoe, but colored her hair to light purple and uses red lenses to seek that "cool" appearance.
- It is confirmed, however, that her hair is naturally curly and requires a lot of maintenance to arrange it.
- In the Re:Zero collaboration, her character design is based on Beatrice.