There is no difference between the energy and the energetic in regard to the Lord's appearance as Śrī Caitanya Mahāprabhu and His four associates—Nityānanda Prabhu, Advaita Prabhu, Gadādhara, and Śrīvāsa. Amongst these five diverse manifestations of the Supreme Lord (as the Lord Himself and His incarnation, expansion and energies) there is no spiritual difference. They are five in one Absolute Truth. For the sake of relishing transcendental flavors in the Absolute Truth, there are five diverse manifestations. These are called the form of a devotee, the identity of a devotee, the incarnation of a devotee, the pure devotee and devotional energy.
Out of the five diversities in the Absolute Truth, the form of Lord Caitanya is that of the original Personality of Godhead, Kṛṣṇa. Lord Nityānanda is the manifestation of the first expansion of the Supreme Lord. Similarly, Advaita Prabhu is an incarnation of the Supreme Lord. These three—Caitanya, Nityānanda and Advaita—belong to the category of Viṣṇu-tattva, or the Supreme Absolute Truth. Śrīvāsa represents the pure devotee, and Gadādhara represents the internal energy of the Lord for the advancement of pure devotion. Therefore Gadādhara and Śrīvāsa, although included in Viṣṇu-tattva, are dependent, diverse energies of the Supreme Lord. In other words, they are not different from the energetic, but they are manifest diversely for the sake of relishing transcendental relationships. The whole process of devotional service involves a transcendental reciprocation in the relationship between the worshiper and the worshiped. Without such a diverse exchange of transcendental flavors, devotional service has no meaning.
In the Vedic literature (Kaṭha Upaniṣad) it is stated that the Supreme Lord is the supreme living entity amongst all living entities. There are innumerable living entities, but there is one living entity who is the Supreme Absolute Godhead. The difference between the singular living entity and the plural living entities is that the singular living entity is the Lord of all. Lord Caitanya is that supreme living entity, and He descended to reclaim the innumerable fallen living entities. In other words, the specific purpose of Lord Caitanya's advent was to establish the Vedic fact that there is one Supreme Personality of Godhead predominating over and maintaining the innumerable personalities of all living entities. Because the impersonalist (Māyāvādī) philosophers cannot understand this, Lord Caitanya advented Himself to enlighten the people in general about the real nature of the relationship between the Supreme and the many entities.