Nakula

The forth born Pandava, son of the Ashvin and Madri, the second wife of Pandu. His twin brother is Sahadeva.

Find the story in the first parts of Mahabharata – from Bharata to Pandu
http://hindumythologyforgennext.blogspot.com/2012/07/mahabharatha-chapter-1-emperor-bharat.html