Lumo is a member of the 10th Squad who is imprisoned in the jail in Marim, Ape Atoll. He and his squad were sent by King Narnode Shareen to oversee the decommissioning of the Shipyard on Karamja, following Glough's defeat. However, the gnome gliders the squad were using as transport were caught in a strong wind, causing them to crash on Crash Island. Lumo accompanied Sergeant Garkor to the nearby Ape Atoll. However, he and two of his squad, Carado and Bunkdo, were captured by the simian natives and thrown in jail.
Glough's agents, G.L.O. Caranock and Waydar, attempted to have the entire 10th Squad killed off with the aid of King Awowogei, the leader of Ape Atoll. They used teleportation magic to transport anybody wearing a 10th squad sigil into an arena where a jungle demon waited, including the three gnomes in prison. However, a human had been inducted into the squad shortly before the ambush was sprung, who fought the demon while Lumo and the rest of the squad provided assistance.
The 10th Squad remain on Ape Atoll to gather intelligence on the monkeys. Bunkdo, Carado and Lumo allowed themselves to be recaptured and remain in the prison.
Lumo keeps track of how often a player is captured and imprisoned. At times, he will instead converse with his fellow gnomes, telling jokes and engaging in sing-a-longs.
After Monkey Madness II, he is located by the exit in the Tree Gnome Stronghold that leads to the Crash Site Cavern.
- After getting caught 100 times, Lumo will congratulate you on the ignoble feat and asks Bunkdo if he should give you a prize. You receive a stuffed monkey.
- His name means "enchantment" or "charm" in Finnish.