The origins of the Devourer are not stated, but players have many different theories about what he is and where he came from.
One popular theory is that he is simply an ancient, powerful beast from the ice realms in the South, and he was captured by The Ice King, only to be freed hundreds of years later.
One less common theory is that he is a creation of The Storm from its last reign over the world, as he looks very much like a Blaster Mist Monster from the Save the World universe. He also has the same ability as the Blaster; he shoots deadly beams from his mouth. And if the theories are correct that The Cube is made from the Storm, it would explain why the Ice King has a Cube shard in Season 7- the Storm had attacked before and summoned the Devourer along with the Cube.
On June 6, 2019, the Monster broke out of Polar Peak, getting rid of the Ice King's castle. However, it was seen twice that The Ice King's castle was not destroyed. The monster was seen swimming on the outskirts of the Battle Royale map with The Ice King's castle on top. After the Monster broke out of Polar Peak, multiple occurrences happened, such as Pleasant Park's modern house destroyed, one of Loot Lake's main buildings gets destroyed (the left one) alongside leaving a Footprint, the far-north house at Snobby Shores destroyed, and footprints West of the Frozen Lake (AKA frozen Greasy Grove).
On July 20, 2019, The Monster rose out of the outside water from North and into the Island. Mecha (the robot built in Pressure Plant) turns on and proceeds to fight it. While the monster is punching the vault in Loot Lake, Mecha shoot rockets into the monster. After that, It shoots some laser beam from its mouth, damaging Mecha. At one point, Mecha tackles the Monster onto the river outside the Battle Royale Island. Mecha then flies out of the water walking forward, and the Monster jumps out on top of Mecha. The Monster damage's Mecha's jetpacks, and tears off the left arm. Mecha then opens the vault and grabs an orb that was from the Unvaulting Event. The orb gave Mecha a powerful punch towards the Monster as it was running towards Mecha. Mecha proceeds to grab the statue in Neo Tilted, which seemed to be the handle of a giant sword. The robot strikes the sword at The Monster's head, killing it. The Monster's skull remained near Salty Springs until the end of Season X.