Jalandhar was born of shiva's fire from his third eye. when merged into the sea. he was born to put halt to the wrong deeds of Indra (DEVA). He was raised by a matsya kanya. when one day he refused to bow Indra. he attacked him with his weapon in the course his mother came between and died of the attack. After that incident he was raised by asura Guru Shukracharya and later become the king of the three loks defeating Indra as well. He married Vrinda (Tulsi) and was respected by every human, Demon, God for his Justice, Principle, Clean thoughts But his growing ambtiton lead him to attack Mahadeva (SHIVA) and acussed him of hypocrisy and injustice. He wanted to become trimurti by replacing Mahadeva and in the course he ignited the shivansh in him to attain maximum power so that he can defeat Shiva . He also said that he will Becalled as "Devon ka dev Jalandhar"
Vrinda Organized a Puja (Worship) for Jalandhar Protection. This could make him immortal and he couldn't be defeated by Mahadeva and Parwati Themselves. So. Vishnu took Jalndhar form and joined the puja and thus ruined everything for Jalandhara. After Knowing all this Plot Vrinda got so much angry that she cursed Vishnu that he will suffer too for his wife as she suffered for his husband. Narayan easily took this curse on him and blessed him that she will be remembered for her honesty towards her husband and will be worshiped in the form of tulsi with him. She later committed suicide. Jalandhar noticing he wife's dead body got so agitated that he attacked kailash with his demon army and aid from yamraj. After many years of fight jalandhar was defeated by the combined power of parvati and shiva. In the end He found his mother and Wife present in shiva beacuse all the universe is contained in him as he is omnipresent, omnipotent and omniscient and after being blessed by Maa Parvati to pursue his triumph journey.He was absorbed by Mahadeva Third Eye in the same form as he was born from it.