How to write a story about a mysterious race that may or may not be a legend?

I want to write a story (or try to anyway), where there is a standard race, you know, something like humans or something like that, and also another race that is rumoured to live nearby and some people have claimed they've seen them but no-one truly knows. How do I approach this? I would especially like to know how to make it more interesting, I don't want people to be terrified of that race but also not having entirely positive feelings towards them. So how can I make it more interesting and less cliché? And how can I have a member of the standard race meet the member of the mysterious race that won't be forced or cliché or boring?
Thanks in advance.