 The Overmind becomes aware of Xel'Naga, attacking and assimilating its masters.Through this, the Overmind learns of the existence of the Protoss and is determined to assimilate the fellow Xel'Naga-empowered species, believing this will result in perfection.To provide the necessary force to overcome the Protoss, the Overmind targets the psionic potential of the Terrans for assimilation.