According to Hinduism there are 33 million Devtas are described in vedas and sastra.
Mahasu Devtas is one of them and worshiped in jaunsar bawar region .There is not any kind of written evidence and history about incarnation of mahasu devta.
the story goes to three thousand year ago before Pandav period in dawapar yugas at that time in Kuru Kashmir (presently in Pakistan) near a Sundarsarover (sunder pound) VimalDev ruled this area with his wife Devladi Mai. they both are ascetic and saintlike .they both have supernatural power.
there is another story behind the incarnation of vimal dev and his other brother
""Ganesh and his sibling Karthik quarreled among themselves about who is stronger
and mightier of the two.They agreed who ever travels around the world and returns
first will be considered to be the mightier than the other.
Karthik started his journey on vehicle- the peacock which started to move swiftly.
Ganesh set out on his journey on his vehicle –the mouse.
While Karthik moved swiftly Ganesh could move very slowly.
Seeing this Ganesh stopped and thought ,”I will surely lose the game if this continues.
I have to think of another plan.”
After much thought he came to a conclusion and turned back.
He went to back to their home,
the abode of snow, the Himalayas where Shiva and Parvati- his parents lived.
He went to them bowed before them and requested them to sit nearby.
They were surprised but agreed and sat on a hill close to each other.
He then bowed them and revolved around them 3 times and sat near by.
When his parents inquired what he is up to do he asked them to wait for sometime.
Soon Karthik came there panting, but with a victorious smile. He beamed and said,
“I have won. I have traveled around the world and returned while you are still here.”
Ganesh was still smiling and replied, “Let us leave the decision to our parents.”
He then turned to their parents bowed before them and said,
“Please settle the dispute between us.
We agreed that whoever travels around the world and returns first will be considered
as powerful as and mightier than the other. Karthik traveled the whole world and is
returning now. But I revolved around both of you three times and am sitting here for
Past some moment . Now tell us who is mightier?”
Both Shiva and Karthik smiled and turned to Karthik and said, “Dear son, your elder brother is right.
Revolving around the parents 3 times is equal to traveling around the world once.As this is
the accepted truth he wins the deal.”""
After this incident kartikay is very angry and depressed and comes near the sunder pound in kashmir and divided whole body in four part .from these four part four devtas is incarnated vimal dev is one of them
and other is Vashuki dev ,Ullal dev,Bhadvana dev other three deities goes to Patal loka but vimal dev is decided to live on earth with his wife devladi mai..just because they ruled in kuru kashmir they are called by name of "kudiya kashmiriya".
After few year they have four children 1)Vasik dev 2)Mahasu dev 3) Pavasik dev 4) chalda dev
.Because of origin of incarnation of their ancestry is maash(part of body) they are called char mahasu .
All the for brother are ascetic and have different type of supernatural power.The many legend tell that the incarnation of lord mahasu is before the pandavas
period because when duryodhan decided to live near uttakashi purola .He prayed to
lord mahasu to owe this land .