Sri Sri Radha Madan Mohan & Gauranga

This procedure of devotional service is known as Avidheya or actions which one is duty bound to do, the initiator spiritual master is the Personal manifestation of Shri Shrila Madan Mohan Vigraha while the instructor spiritual master is the Personal representation of Shri Shrila Govinda Deva. Both these deities are worshipped in Vrindaban. Shrila Gopinath ji is the last attraction of spiritual realisations.
(1960 Back to Godhead vol 3 part 16 – Identity of Lord Chaitanya)

Kṛṣṇa is one, but when Kṛṣṇa wants to enjoy, He must expand His pleasure potency. That is Rādhārāṇī. Rādhā kṛṣṇa-praṇaya-vikṛtir. Kṛṣṇa cannot enjoy anything material. The original spiritual potency, pleasure potency, is Rādhārāṇī. So first of all He expanded, then again He combined together. That is Śrī Kṛṣṇa Caitanya Mahāprabhu. This is the study of the Gosvāmī. Rādhā kṛṣṇa-praṇaya-vikṛtir hlādinī.
Therefore Caitanya Mahāprabhu is given seat along with Kṛṣṇa. He's combination of Rādhā and Kṛṣṇa. We may not misunderstand that Caitanya Mahāprabhu is . . . imitating Caitanya Mahāprabhu, there are so many so-called avatāras. But this is approved by the śāstra. Kṛṣṇa-varṇaṁ tviṣākṛṣṇam (SB 11.5.32). Caitanya Mahāprabhu is Kṛṣṇa, same category, kṛṣṇa-varṇaṁ. Just like we say varṇa: brāhmaṇa varṇa, kṣatriya varṇa, śūdra varṇa, vaiśya varṇa. Varṇa means the same category, varṇa. Or kṛṣṇa-varṇaṁ means who is always describing Kṛṣṇa. Just like Caitanya Mahāprabhu is passing on the road, He's chanting,
kṛṣṇa kṛṣṇa kṛṣṇa kṛṣṇa kṛṣṇa kṛṣṇa kṛṣṇa he
kṛṣṇa kṛṣṇa kṛṣṇa kṛṣṇa kṛṣṇa kṛṣṇa kṛṣṇa he
kṛṣṇa kṛṣṇa kṛṣṇa kṛṣṇa kṛṣṇa kṛṣṇa pāhi māṁ
(CC Madhya 7.96)
Therefore kṛṣṇa-varṇaṁ is He; iti kṛṣṇa. Kṛṣṇa is describing Himself: kṛṣṇa-varṇaṁ tviṣākṛṣṇam. But by His complexion, He is not black—very fair complexion.
(730306 - Lecture BG 10.01-3 - Calcutta)