Kacha was the son of Guru of Devtas ( Brahspati ), he was sent to Shukracharya to learn Sanjivani Vidya. He went and requested Shukracharya as his disciple, which request Shukracharya accepted. In the meantime he become close to Shukracharya’s daughter Devayani. Devayani falls in love with him.
Asura wanted to kill him as they were ware of his purpose to learn Sanjivani Vidya. Every time Asura killed him, Shukracharya revived him with Sanjivani Vidya on the request of Devayani. The Asuras finally killed him and mixed his remains with divine water and served it to Shukracharya. Shukracharya unknowingly consumed the divine water, and when he tried reviving Kacha, he realised that Kacha was in his stomach. So he was forced to teach this Sanjivani Vidya to Kacha, who came out tearing open his guru’s stomach.
Kacha then revived his guru with his newly learnt Sanjivani Vidya.