They had never intended to join the allied army, nor their baffling operation. They were just using their cover identity to get through checkpoints in Osidian Plain. Once they were in, they needn't to stay put in one place like needle to the pole.
The allied army wasn't just an army right from the beginning; it had massive supplies and weaponry, logistics and auxiliary units had turned the vast land of Osidian Plain into cities. Barracks and towns were scattered within the million-square-kilometre area connected by web of roads. No one would have believed that one year after the war Obsidian Plain would be developed into its present state. The large army and complex of barracks had provided an ideal cover for Hao Ren to move around.
