This paper examines the nature of the transcendent, absolute, and personal host of ancient philosophical notions of the Higher Power (天觀 cheongwan, literally 'view of heaven'), which flows through Toegye's Principle of Reality (Li), Dasan's Supreme God (Sangje), Suwun's Lord of Heaven (Cheonju), and Jeungsan's Supreme God (Sangje). This confirms the sentiment that despite the conceptual differences relating to appearance, as represented by the Principle of Reality, the Dasanian Supreme God, the Suwunian Lord of Heaven, and the Jeungsanian Supreme God, the contents of these notions do not substantially differ from one another. Moreover, the nature of the ancient philosophical notions of the Higher Power lead to Toegye's Principle of Reality, the Dasanian Supreme God, the Suwunian Lord of Heaven, and the Jeungsanian Supreme God. Toegye emphasized the nature of the Principle of Reality as transcendental and absolute, and also as a personal host. This led to Dasan's Supreme God, and furthermore, it also inspired the Suwunian Lord of Heaven and the Jeungsanian Supreme God. In other words, although Dasan criticizes the Principle of Reality and presupposes a Supreme God, a personal host, this is not especially different from the character or role of Toegye's Principle of Reality. It likewise does not especially differ from the Suwunian Lord of Heaven or the Jeungsanian Supreme God. On the contrary, without the foundation of the religious tradition behind Toegye's Principle of Reality, it would have been difficult to establish a theoretical system leading to the upper system of the Dasanian Supreme God, the Suwunian Lord of Heaven, or the Jeungsanian Supreme God. Of course, the construction of heaven and earth, which in Daesoon Thought is actually performed by the Jeungsanian Supreme God, is, in fact, fundamentally different from Toegye, Dasan, and Suwun's previous notions of the Higher Power. In this sense, it is necessary to present more clearly the religious character of Toegye's Principle of Reality.