I cannot fully comprehend your post,
When you register a domain, you must decide who the DNS authority is.. it is very much possible to use only 1 name server, but most have additional servers setup to mirror the configuration of the primary server.. for redundancy and backup purposes.
If your registrar requires 2 name servers via some sort of automated configuration panel, consider emailing a technical support representative and see if bypassing it is possible.
Another option
http://freedns.afraid.org/secondary/, many similar services exist.. but this is the most popular, and it's free.
Good luck..