In multiple portrayals of the Samudra Manthan, a man is seen in the waters, pulling from neither side. His dressing style makes him look like a Persian. Who is this?
His dressing style makes him look like a Persian.
Yes, he looks like a Persian because these paintings were drawn during the reign of Mughal emperor Akbar. Most of these paintings were drawn by a painter named Mushfiq and other painters of that time. He contributed to a lot of paintings for Persian versions of Ramayana and Razmnama. Razmnama which means book of War is a Persian translation of Mahabharata. Akbar endorsed the work of translating Rajatarangini, Mahabharata and Ramayana to a few translators into Persian language.
According to Wikipedia article on Razmnamah,
In 1582 an order was passed to translate the Mahabharata into Persian. The translation work of the Mahabharata, which has one lakh (100,000) Slokas, was carried out during the period 1584–1586..............Mushfiq has contributed the paintings to this book. The speciality of this Razmnamah is the paintings of the events of Mahabharata in the book.
The paintings you uploaded in the question are depicting Churning of the Ocean. This is mentioned in the Mahabharata also. In the scene, different articles are being churned out of the ocean and Devatas and Daityas are collecting them from either sides.
This is inline with the original Mahabharata. We can see Airavata, Moon God, Kamadhenu etc., coming out of the ocean. The man who is in Persian attire is Dhanvantari.
From Chapter 18 of Adi Parva where Samudra Manthan is mentioned,
Then Lakshmi, Soma and the Steed, fleet as the mind, all came before the gods on high. Then arose the divine Dhanwantari himself with the white vessel of nectar in his hand. And seeing him, the Asuras set up a loud cry, saying, 'It be ours.'
So, it is Dhanvantari. We can see all other outcomes like Airavata, Lakshmi, Apsaras, Moon, Kalpa Vriksha, Kamadhenu, Uchhaishrava in the paintings. Only man missing is Dhanvantari
It is not surprising to see Dhanvantari in that attire as the paintings clearly show the patronage of artists during Akbar’s reign. Not only here, many paintings were drawn to reflect the attire during Akbar Reign. Arjuna and others were shown participating Kurukshetra war in similar Persian attire.