Musubi Matsukata, more commonly known by her in-game avatar name YUI, is someone the protagonist meets when he first logs in to an online MMO called Harvest World Online. A cognitive manifestation of YUI as a phantom idol was created by Merope from Nagisa Kamishiro’s cognition, also known under the codename BUI. She is noted to be extremely passionate about farming, and tries to buy the land that the protagonist obtains as a bonus. After a negotiation, the two agree to co-own the land and use it for farming. Behind the screen, YUI's operator is a lady named Musubi Matsukata, who works as a system engineer in an IT company with its office located in Shibuya.

Voice Description: Medium-high female vocal range. Mostly seen as YUI within the game, she is very energetic and friendly, always willing to lend the protagonist a hand.