The Unimplemented Overlords Have Joined the Party! Novel Volume 3 was written by Nagawasabi64.

With the invasion quelled, Barbara and the members of Party 21 add two new recruits—Rao and Reilan—to form Party 7, which sets out for the next town. Meanwhile, Wataru's group has made it all the way to the front line at Fort Sandras, where they join forces with the three top progression guilds. There, Misaki meets a player who tells her where to find the person who saved her life! As the Mother AI's goals start coming to light, will Shuutarou, Wataru, and Misaki's stories finally converge?!