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

I want to write a story (or try to anyway), where there is a standard race, te know, something like humans o 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 più 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 più 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 o cliché o boring?
Thanks in advance.