Since Amon started his seclusion, he decided to end it when he broke through to the Martial Realm. He could continue cultivating under seclusion and would eventually reach the Lord Stage. However, doing that would mean throwing away everything he built during his time at the Royal Academy.
He had confidence in his underlings, but like everything, there was a limit. No matter how strong his underling's belief in him, it would still degrade with time. If he stayed absent for a hundred years, or maybe even half that time, he would find no one remembering him by the time he returned to civilization.
He believed in individual prowess but also understood not to neglect organizational power. This world might be able to turn an individual into a God-like being, but the power of many was still real. To achieve the great thing he planned, he needed that power. The power to band people into his service and that power required nurturing.
