Yun is a 17 year old hacker who joins Kazuki and team. She is playable in Emma's storyline. The moment when she joins depends on the result of battle in Wilson Cliff, Australia. If the player succeed in destroying Cadenza transport, the team will gather information about air transport shooting in Sumatra. The information will lead the team into the battle with OCU, together with Sumatra Guerilla lead by Hatta Mirza. After the battle, Hatta will bring the team to Singapore to meet her.
If the team fails to destroy Cadenza transport, the team will meet her in DHZ mainland, precisely in Hua Lian headquarter where she suddenly sneaks in to offer for "help".