Luv and Kush were the children of Lord Ram and his wife Sita. After Sita was banished from the kingdom of Ayodhya, she took shelter in the ashram of Valmiki, which was based in a forest on the banks of the Tamsa river.
Luv (Lava) and Kush were born in this ashram of rishi Valmiki. They were educated and trained by rishi Valmiki. One variation of the legend interpreted the origin of Lava’s twin brother Kush.
Once, Sita was going for a bath to the nearby river (tamsa), and while she was going for bath she requested muni Valmiki to take care of her son Lava, and muni nodded his head as he was busy writing. After going some steps she observed that muni was continuously immersed in writing, so she took Lava with herself.
After some time when Muni looked for the child who was supposed to be with him, he could not find Luv. Muni was not aware of the fact that Sita herself had taken Luv with her. Muni was concerned what he would say when Sita wil return and ask for her kid.
So he made a child from nearby Kush (a grass utilized for producing mats and roofs of kutiya’s in ancient India) and gave life to it. When Sita returned, Muni was surprised to see that Luv was with her, so he asked Sita to take care of both children as her own children. Since Valmiki muni used Kush to make the child, the child was given the name Kush.
Lava and Kush were born in Maharshi Valmiki’s ashram. Before their birth Sita had requested Valmiki to accept her kids as his disciple. Valmiki basically started education Lava and Kush when they were around 5 years of age. He trained them in archery and they were able to launch arrows at the speed of sound.
He also trained them about divine & celestial warfare. He made them masters in archery so that nobody on this planet could conquer them in war. He established a connection between his mind and Lava and Kush’s mind and directly transmitted all his knowledge to them.
After military skills, he taught them the art of singing and playing the veena. He taught them the Ramyana, which was written by Maharshi Valmiki himself, keeping Rama as the center point. Later, Luv and Kush used their singing skills to infuse love for Sita in the Ayodhya’s people.
When Rama carried out the Ashvamedha Yagya, the horse strayed into their forest, which brought them into conflict with their own father. Not aware that Rama was their progenitor, they captured the horse and declined to release it. They engaged in conflict and defeated Ram’s brothers (Bharata, Shatrughna and Lakshmana) with ease.
Eventually, Rama himself came to confront them in battle, but after witnessing their prowess, he invited them to Ayodhya to perform the Yagya. It was at that point that he learned of their identity as his sons.