The Jambastion Cult is the main antagonistic faction of Kirby Star Allies. They are an alien religious order centered around worship of the destroyer deity Void Termina. They seek to gather the Jamba Hearts so they can use them to revive Void Termina.
Vowing revenge, in the present day, Hyness sent the three Mages to gather the Jamba Hearts so they could revive Void Termina and summon him to their world.
By the time Kirby and company made their way to confront Hyness, he was already summoning the Jamba Hearts from across the universe to revive Void Termina. After fighting and being defeated by Kirby and his friends, Hyness realizes that he does not have enough power to restore the Dark Lord and sacrifices the Mage Generals and himself to revive Void Termina.
During the fight with Void Termina's core, the heroes manage to free Hyness and the Mages from Void Termina's insides. They are then spat out into the vacuum of space. It is unknown what happened to them after that.