Narnarayana

Vishnu as God (Narayana) and Human (Nara).

Nara and Narayana are twins of Murti, a daughter of Daksha. She prayed to Vishnu, to free humanity from the demon Sahasrakavacha.

Im Mahabharata are Krishna and Arjuna Naranarayana.

The story of Sahasrakavacha is the first part of the life of Karna.
http://hindumythologyforgennext.blogspot.com/2012/09/karnas-karma.html

Read about Narnarayana here
http://hindumythologyforgennext.blogspot.com/2012/09/the-birth-of-uruvashi.html