Shangri-La Frontier manga volume 12 features story by Katarina and art by Ryosuke Fuji.

While looking to gather information about Ctarnidd, Sunraku unintentionally gets thrown into a bonus scenario that seems lethally dangerous. Alone in an undersea city full of vicious enemies and separated from his party, Sunraku has 170 hours to clear the scenario. Fortunately, Sunraku meets Araba, a friendly npc. Araba helps Sunraku get a better understanding of the environment and together they begin the search for Sunraku's friends. However, time is limited and Sunraku must honor his promise with Katzo to fight in the GGC. Logging off to go fight in a pro gaming competition might be what ultimately ruins Sunraku's chances of clearing the scenario, but with his party members holding the fort, perhaps there's a chance…