Cymark

From publisher blurb:

At heart, the Cymark are a xenophobic and highly aggressive species that shows no regard for the lives and property of other beings. For them, the fact that such things as non-Cymark civilizations even exist is an intolerable offense - a blight upon the purity of the Universe.

Still, they have not attempted interstellar genocide. Yet.

So far, they have settled for destroying anyone who comes within their reach, slaughtering everyone and stripping the place bare - ships, outposts, even entire colonies. Simply traveling near Cymark space is considered a high-danger occupation. Few independent pilots will dare to do so, at least without a full military escort. And even then, they might think twice.