Lord Rāmacandra and His brothers, Lakṣmaṇa, Bharata and Śatrughna, are all viṣṇu-tattva, not jīva-tattva. The Supreme Personality of Godhead expands into many, many forms. Advaitam acyutam anādim ananta-rūpam. Although they are one and the same, viṣṇu-tattva has many forms and incarnations. As confirmed in the Brahma-saṁhitā (5.39), rāmādi-mūrtiṣu kalā-niyamena tiṣṭhan.