Pseudo Soul

Pseudo Souls (擬似魂) are a device developed by Rimuru to be a vessel for the heart, and are based on the core mechanics of Sarion's Homunculus. Rimuru used pseudo souls as the base to hold the Chaos Cores of Treyni and the rest of the Dryas Doll Dryads. These devices have not been mass produced by Tempest yet, making Rimuru the only known source for them. In the anime, they are depicted as yellow orbs.

By embedding pseudo souls into monsters generated through a Master Core (魔精核), it is possible to create an Avatar (仮魔体), a temporary body that the user can possess much like a Homunculus, with an Avatar Core (魔魂核). The Dungeon Dominators are one example of this, while in Gaia's case, its avatar was the body it was reborn in.