Choco, introduced in 2016 for LINE's fifth anniversary, is Brown's younger sister. She sports lighter fur than her brother and consistently wears clothing: a pink or peach head bow, a pink jacket, a white dress, white socks, and yellow shoes, often paired with a yellow bag featuring a pink heart-shaped button.

Unlike her silent brother, Choco exudes a sociable and outgoing personality, marked by a passion for gossip and a strong interest in fashion trends. She actively uses social media, frequently sharing selfies and maintaining an Instagram account to showcase her style. While initially shy like Brown, she becomes more comfortable interacting with his friends once acquainted. Her interests include sweets and staying updated on the latest fashion.

Choco appears across numerous episodes in multiple seasons, sometimes in a main role and sometimes supporting. Her appearances include episodes like "James the Party Animal," "Silent But Deadly," "Brown I Shrunk the Friends," "Drip Drip Drop," "Luchador Next Door," "Friendsgiving," "Bad Boy Brown?," "Boom or Bust," "Choco Latte," and "Sally Kong Zilla." The series conveys her interactions and personality through visual expressions and actions without dialogue.

She is recognized as the first female character in the LINE Friends universe with a sibling among the main characters and the first to consistently wear clothing. Her name complements Brown's, forming "brown chocolate," referencing the common color of chocolate. She shares a birthday with James. Merchandise featuring Choco includes official stickers, dedicated LINE FRIENDS STORE products, and items like branded gel pens.