Pseudo Soul

Pseudo Soul (擬似魂) is a device created by Rimuru based on the core mechanics of Sarion's homunculus. It was developed to be a vessel for the heart core. Treyni and the rest of the Dryas Doll Dryads have their chaos cores housed within pseudo souls. They 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. The Dungeon Dominators are one example of this, while in Gaia's case, its avatar was the body it was reborn in.