How did Lord Sri Ram and Lakshman departed from the earth, Padma Purana
Whoever is born on this earth has to die some day, no one is immortal. The same case applies to every god who took incarnation in this earth, all who came on this earth had to leave some day and they left in different ways.
Many gods were born on this earth to fulfill some things for the greater good. We are talking about the incarnation of Lord Ram and Lakshman who were born on the earth to full fill certain purpose and when the purpose was over they had to leave the world. When Ram’s and Lakhsman’s time on earth came to completion, they themselves arranged their departure to the death. The story of Lord Shriram's death is recorded in Padma Purana.
One day, death came in the court of Shri Ram in Ayodhya. Shri Rama knew in advance that it is his time, the death has come to say him that his time was over from the earth. Ram took the death, in the form of saint to a room and ordered his younger brother Lakshman to be punish anyone, if they tried to disrupt his discussion with the saint.
Laxman was following the command of Ram by standing at the door, at the same time Rishi Durvasa arrived and talked of meeting Shri Ram.
On Lakshman's refusal, Rishi Durvasa warned that if he was not allowed to meet Rama then he would curse Raja Ram of Ayodhya.
Lakshman was afraid to hear the curse of Durvasa Rishi and felt that it is better to enter the room and have a talk with his brother, he thought it was better that his brother gave him the death sentence in violation of the order. So he entered that room Where Shri Ram was talking to the elderly saint, however the saint was in the real form or death. No Human being has ever seen death in true form, As Lakshman had seen Death, Ram Instead of giving death to his brother and He punished him with exile from the country. Lakshman exile from the country was even harsher than the death penalty. Lakshman did not want to live for a moment without his brother, and he decided that he would give up his life by taking water Samadhi in Saryu River and took the divine formation of Sheshnag and went into the river.
Shriram and Lakshman cannot live without each other, after Lakshman's departure, Shri Ram also decided that he would give up this world now. In this way, Shri Ram handed his palace to his sons and sons of his brother and left for Saryu.
Like Brother Laxman, Shri Ram also proceeded inside the Saryu and went into the middle and took Samadhi. In this way, Shri Ram left his human form and embraced his true nature, which was of Lord Vishnu. Shree Ram went to Vaikunth Dam after assuming the form of Vishnu.
This happened in the death of Shri Ram and Laxman!