Magecrafter
No. The mastermind is that one cowardly guy who works with REY, NOAH. He has the resources, skills and knowledge to do so. Cowardly behaviour is just an act of him putting on to deceive people and REY. Resources - large amounts of money from working with REY and he can buy everything from that black market store since those guys thought REY was a big shot and Noah is his subordinate. Skills - he’s able to freely leave and enter the palace with his thief skills, he might be able to steal some important items/artefacts. Knowledge - REY just told him about where he earned his monsters cores, now he lost everything. What a coincidence!!! More than one is longer normal.