Bhakti takes a different shape in each of Hinduism's theistic denominations, organized around whichever deity that tradition holds supreme, yet the underlying grammar, loving surrender as a path to liberation in its own right, stays constant across them. Vaishnavism built the largest and most textually elaborate bhakti literature around Vishnu's avatars, especially Krishna and Rama, running from the Bhagavata Purana's extended devotional narratives through the Alvar poet-saints of Tamil Sri Vaishnavism to the ecstatic Krishna devotion of Bengal's Gaudiya tradition. Shaivism developed a parallel devotional literature centered on Shiva, most fully in the Tamil Nayanars, whose hymns were later canonized as the Tirumurai, and Shaktism directs the same devotional grammar toward the Goddess, addressed with the intimacy of a child toward a mother even where her forms are fierce.
Because bhakti asks for surrender to a particular, personal deity rather than knowledge of an impersonal absolute, it sits in real philosophical tension with the more austere non-dualism of Advaita Vedanta, which historically treated devotion as a preparatory discipline for the seeker not yet ready for direct knowledge rather than as liberation's final path. Ramanuja's Vishishtadvaita and Madhva's Dvaita, by contrast, built bhakti directly into their core metaphysics, since both hold souls to be genuinely, permanently distinct from God and therefore capable of a real devotional relationship that non-dualism's final merger would erase, which is part of why bhakti has flourished most richly inside Hinduism's theistic rather than strictly non-dualist schools.