Unofficial biography, made by me. Contains lots of spoilers for the series. I will make a spoiler-free biography soon. Largely incomplete.

Name: Akane Shijou
Age: 17
Birthday: February 23rd
Eye Color: Carmine
Location: Kyoto
Hair color: Silver
Favorite color: Red
Personality: Hyperactive and outgoing
Voice Actor: Kana Tsukimori
Debut Episode: Season 1, Episode 1
Nicknames: "Akane-chan" (herself)
Current status: Alive
Name Meaning: Her first name means red (赤) and her last name means sound (音). Her last name means four (四) and article (条).
Quote: "WAHAHAHAHAHAHA!!!!!"

Akane Shijou is a 17 year old girl who has the maturity of a 5 year old. She loves to eat dagashi (cheap Japanese snacks) and drink lots of soda. She is very hyperactive and nimble. She often bothers her big sister (Takane) in her free time. She was raised by her biological parents, unlike her big sister. However, whenever she tries to dance, it looks like she's having a seizure, and her singing is very off-key, which makes her more disliked.

When Azusa Miura was introducing her little sister, Matsu, to Takane, Akane came in and then tackled Matsu, causing Matsu to be scared of Akane. Takane calls Akane a "big embarrassment, yet we still love her."

She goes to the same school as her best friend, Midori Yamaguchi (山口 緑), and is the leader of her dance club, although no one, except Midori, goes to it. Surprisingly, a blue-haired social outcast, Chihaya Kisaragi, actually appreciates Akane's attempts to dance, causing Akane to become one of Chihaya's only friends. Often, whenever Akane sees Chihaya with someone else, she calls the person Chihaya's lover, embarrassing her.

Facts
Her favorite food is ramen. She eats lots of it, and she has a huge appetite as well. Do not take away her ramen, or she'll have a seizure.
She was raised by her biological parents, while her sister, Takane, was raised by her biological parents.
The creators probably were inspired by Akane Nonohara, from the IdolMaster Million Live, as they both have hyperactive personalities.