(The SH in this name is pronounced like one between the 's' in 'sip' and 'sh' in 'ship'. In the alternative name, the N is pronounced like 'n' in 'name'. The last S shows it is a plural number, only in English spelling, but not in Samskritham, where it is always a dual number. Remember, in Samskritham, there are three numbers, single, dual and plural.)
These two are a batch gods. They are very handsome. They are the doctors of the celestials. In Mahaabhaaratham, they booned two twin sons Nakula and Sahadeva to Paandu's younger wife Maadri. That is why Nakula was so handsome in form.
The Aadi parva describes how these gods were allowed by Indra a share in the sacrificial offerings alongwith other gods.