The third faction featured in "Tiberium Wars" is an extraterrestrial force is known as the Scrin, which is trying to terraform Earth with Tiberium and harvest Tiberium deposits.
The third faction, which only appears in "Tiberium Wars" and its expansion pack "Kane's Wrath", is an extraterrestrial force known as the Scrin. Its goal is to terraform Earth with Tiberium and harvest Tiberium deposits.