The Foolery and Robert limited themselves to spread their influence while following King Elbas and Noah. The ground under them continued to mutate even after the group moved forward, and only Alexander remained a bit behind to make sure that everything worked perfectly.
Alexander didn't have any unique talent suitable for that project, but his countless abilities made him able to inspect the environment far better than some of King Elbas' inscribed items.
The hybrid could use abilities with different purposes and elements to inspect the landmass from various perspectives. Moreover, Alexander had multiple skills that gave him the power to fix or complete flaws that the mutations could create.
Alexander didn't do much in the end. It was almost impossible for flaws to appear after the ground went through mutating auras, spreading inscriptions, and Noah's ambition. He limited himself to check that everything was okay, but his journey soon became quite dull.