This is Madhvacharya, one of the great philosophers of Vaishnavism, a major sect of Hinduism. He is a sanyasi, a person who renounced worldly belongings and embraced austerity. He is a historical figure and said to have lived in the twelfth century.
Here he is standing on a turtle wearing only a loincloth, called Kaupina. The turtle marks Vaishnavite affiliation and deifies the figure. In his right hand, he is holding Akshamala and is supporting his ‘Dhanda’ with the right hand. His right thumb and index fingers are joined at the tip in teaching gesture, cinmudra. He is holding palm leaf manuscript (Pustaka) and Kamandala in his left hand. Deft casting.
His ornaments is minima, just a necklace. Likely to be a Tulsimani mala rather than anything made of precious metals.
According to Gururaja Bhatt, Studies in Tuluva History and Culture, Madhvacharya was responsible for synthesizing various cults of Tulu Nadu under Lord Vishnu.
The figure is about 7.5 cm in height. It is quite likely the casting is from North Karnataka/Western Deccan.
Note (20 March 2021): The earlier Madhvacharya vigraha, a Ganga-Jamuna one, is with one of my friends and he wanted it for his home altar. On his request I have removed the earlier pictures.
Not too long ago taking pictures of deities in worship was a forbidden practice. Now-a-days there are dedicated TV channels to show temples, deities, festivals, puja and abhisheka. Even the heads of the sects are seen posing with Vigrahas. At the same time some of the earlier practices continues, like my friends request to remove the picture as the Vigraha will be under worship.
For me it is interesting to see the way ideas and social norms propagate through the society.