After the Mahabharata War was over,only Ten remained alive, Three from the Kaurava Side and Seven from the Pandavas. They are,

Pandavas 5

Lord Krishna,

Sathyaki.

From the Kaurava Side Aswathama, Kruthavarma and Krupa.(Mahabharata ,Adi Parva)

At Dwaraka, the Yadava Clan was in tact, save those killed in the Mahabharata War( Krishna’ Army fought on the side of the Kauravas)

The Yadav Clan were playing around and one of the Yadavas dressed up Krishna’s son Sambhava(born of Jambavathi), as a pregnant woman and asked the Rishis who were passing by, what child the lady would beget(Sambhava)

The Rishi replied that knew that it is Krishna’s son Sambhava and he would beget a  Pounder (used to break Grains- Ulakkai) and it it would destroy the Yadava vamsa.

On being informed of this Lord Krishna smiled and said that no body can change the Curse of a Brahmin.

After ten months a Pounder was born of Sambhava.

Thinking that they were clever, the Yadavas, broke the wooden pestle(Ulakkai) into small pieces an threw them into the sea in Dwaraka.

The tip of the pestle,made of iron was swallowed by a Fish, and it was caught by a Fisherman.

He found the piece and fixed it to the tip of his arrow.

The wooden pieces  reached ashore and grew into a bush of Long Grass.

While this is so, one day the Yadavas were drinking and an altercation ensued as who betrayed the Kauravas the most.

A riot ensued and even Krishna was attacked by his Clan.

His Chariot was dragged into the sea, so were His Panchyutas, which went perambulated Lord Krishna clock-wise and disappeared.

From the Balaram’s face a Serpent came out and entered Heavens and Balram was no more

Lord Krishna lay under a tree and was taking rest.

The hunter who had the iron tip in his arrow , from a distance saw, thought he saw a Deer and sent in his arrow.

It struck Krishna and he left His Mortal Coil.

The Hunter prayed for forgiveness.

Krishna informed him that it was because of the Curse, he had nothing to do with His Death and granted him Vaikunta.

As there were none to perform the last Rites,Arjuna performed the last Rites of Krishna.

Krishna’s Father , Vasudeva was the brother of Kunti (Mother of the Pandavas)

Krishna and Arjuna were First Cousins.

Arjun married Subhadra (Krishna’s Half-Sister)

The nearest surviving relation on the mother’s side were the Pandavas.

Technically Yudhistra should have performed, being the eldest off the Pandavas.

*Arjuna could have performed the last Rites because, in addition to being Krishna’s cousin, he was also marrired Krishna’s half sister (  smriti grants this Right if no others are available) and As Krishna put it in Bhagavad Gita, Arjuna was His dearest Friend and as Arjuna put it Arjuna was Krishna’ most deovted  Disciple.)

*Purana merely states Arjuna performed Krishna’s last Rites. The interpretation is mine, based on Smriti.

Deavaki ,Vasudeva and Rukmini left their bodies by entering Fire.

(Bhagavatha Purana)

https://ramanisblog.in/2013/11/19/who-performed-the-final-rites-of-lord-krishna/