Supreme Lord Sree Balarama
Supreme Lord Sree Balarama, serves Supreme Personality of Godhead Sree Krishna in His five Forms of Sree Maha-Sankarsana, Sree Karanodasayi Vishnu, Sree Garbhodasayi Vishnu, Sree Ksirodasayi Vishnu and Sree Anant-Shesa.
Srila Bhakti Vinod Thakur has written as follows in the Amrta Pravaha Bhasya (commentary) of Sri Caitanya Caritamrta:
Sree Balaram, Who is one of the First Four Expanded Forms of Sree Krishna in Dwaraka, can be called the Original Sree Sankarsana. He is Sree Maha-Sankarsana in the second manifested expanded Four Forms of Sree Narayana in Vaikuntha. He serves Sree Krishna by taking the Form of Sree Maha-Sankarsana amd Four other forms i.e. Sree Karanodasayi Vishnu, Sree Garbhodasayi Vishnu, Sree Ksirodasayi and Sree Anant-Shesa. He Himself, while assisting in the pastimes of Sree Krishna, with the four Forms of Sree Maha-Sankarsana, Sree Karanodasayi Vishnu, Sree Garbhodasayi Vishnu and Sree Ksirodasayi Vishnu, does also the work of creation. Sree Shesa Who is known as Sree Ananta performs a variety of Sree Krishna’s service. In this way, Sree Balarama tastes the divine nectar of the service of Sree Krishna accepting all these Forms.
sei ta’ ‘ananta’ ‘sesa’—bhakta-avatara
isvarera seva vina nahi jane ara
sahasra-vadane kare Krishna-guna gana
niravadhi guna ga’na, anta nahi pa’nasanakadi bhagavata sune yanra mukhe
bhagavanera guna kahe, bhase prema-sukhechatra, paduka, sayya, upadhana, vasana
arama, avasa, yajna-sütra, simhasanaeta murti-bheda kari’ Krishna-seva kare
krsnera sesata païa ‘sesa’ nama dhare
(Caitanya Caritamrta, Adi-lila 5.120-124)
“That Sree Ananta Shesa is the devotee avatara of Godhead. He knows nothing but the service of Lord Krishna. With His thousands of mouths He sings the glories of Lord Krishna, but although He always sings in that way, He does not find an end to the qualities of the Lord. The four Kumaras (Sanak etc.) hear Srimad Bhagavatam from His lips, and they in turn repeat the glories of Lord to be immersed in the ocean of transcendental bliss of love of God. Sree Ananta Shesa serves Lord Krishna by assuming the forms of the Lord’s umbrella, slippers, bedding, pillow, garments, easy chair, residence, sacred thread and throne. He is thus called Lord Shesa, as He is the last manifested Form of Sree Krishna to serve Him. He takes various forms for the service of Krishna.”