The Mechnauts were created by Dimirti and were used for his helpers to the Echidna Cop-o-dueat of Angel Island for the Dark Egg Legion. Then the Subspace army brainwashed them as Foot Soldiers and made them work for them. They served Nightmare and the Koopa Empire's SWATbots when their old SWATS were destroyed by Finn. before that they served as Halberd Guards to aid the Primids. Then When the Subspace was back they became the foot soldiers under orders of Roogoo.