Parsvanatha was the 23rd tirthankara of Jainism. He was very popular and belonged to Ikshvaku dynasty like other tirthankaras.
He has a lot of temples across India, the most popular of which is at Shikhar Ji, also known as Parsvnatha hills where it is believed he got Moksha. There is another temple that belongs to him which is present in Nakoda, Rajasthan known as Nakoda Parsvnath. It is extremely popular Jain temple but the most popular deity there is not Parsvnath but Bhairav! Because the area is Nakoda, he is known by the name of Nakoda Bhairav.
In his lower left hand is the Damaru and in upper left hand is Trishula so he is the same Bhairava which can be found in many Shiva temples. The story of the origin of this idol in Nakoda goes like this:
There are stories of Jain statues that were hidden underground to protect them from attacks by intolerant rulers and chieftains during the first half of the second millennium. Many such statues were forgotten and some are still dug out today. The statue of Pārśvanātha or Lord Pārśva in Nākoḍā – Nākoḍā Pārśvanātha – was rediscovered in this way in 1455. According to the story, a Jain lay man had a dream in which Nākoḍā Bhairava told him of the long-forgotten statue of Pārśvanātha or Lord Pārśva, the 23rd Jina, and where it was hidden. The statue was then discovered and installed in the Nākoḍā temple by the Kharatara-gaccha monk Kīrtiratna-sūri. As Kīrtiratna-sūri was carrying the rediscovered statue of Pārśva, people spontaneously formed a procession behind him. They saw Nākoḍā Bhairava in the form of a boy dancing and walking with them, eventually causing them to stop in Nākoḍā. Kīrtiratna-sūri decided to keep the Pārśvanātha statue there and installed the aniconic image – piṇḍākar – of Nākoḍā Bhairava by the temple entrance.
According to the story, Bhairava was extremely happy to see the Parsvnath idol which is pretty odd because Bhairava has nothing to do with Jainism. So there has to be something special in Parsvanatha that made Bhairava very happy. I think Parsvanatha might be an avatar of Shiva. Interestingly enough, Parsvanatha was born in Kashi, the city of Shiva.
Another unique aspect of Parsvanatha is that he is associated with snake. When I read snake and Shiva, it only reminds me of Vasuki so could that mean Parsvanatha was avatar of Vasuki?