Adhyaya 63

During the circuit of Rāma’s Aśvamedha horse, Lava is struck down in battle, rendered unconscious, and taken captive. The grievous news reaches Sītā through distressed young girls; she laments the injustice of a king fighting a child and collapses in sorrow. Kuśa returns from Ujjayinī after worshipping Mahākāla and learns of Lava’s capture. Vowing to rescue his brother, he receives Sītā’s blessings and divine weapons and hastens to the battlefield. The twins drive the army into flight in opposite directions, and the conflict swells. Śatrughna confronts Kuśa and questions his identity; though he realizes Kuśa is Sītā’s son, he still fights. Astra and pratyastra are exchanged—fire against rain, wind against mountain, vajra, and even the Nārāyaṇāstra—until Kuśa swears to fell Śatrughna with three arrows and strikes him down, winning the victory remembered as Kuśajaya.