Hesitants

The Toletta, or Hesitants, are a client race of the Compact of Species residing in a globular cluster. They were originally a small interstellar nation before an unknown swarm of alien beings destroyed the young civilization. Only one isolated colony survived, and is the home of all remaining Hesitants. Now, they remain in their colony, paranoid and deeply xenophobic.

Description
They're not considered to be racially insane, just paranoid and with deep cultural scars from their encounter with the Locusts. Now, they're victim and victimizer both. In the long run, it's a good thing that they encountered the Compact when they did, since if they had started to expand into the galaxy, they would have come across other species, few of which could defend themselves from a xenophobic aggressor that believes all other alien life is either out to get them, or will be out to get them.

Hesitants don't tend to leave their own worlds. They're either comfortable where they are, or their main concern is removing the Compact from those systems."

History
"The Hesitants used to be the Toletta ("New People"), of the Torvis ("New Beginning") Collective. They were once a starfaring species known as the Lett, until something terrible befell their people. Their nation, and most of their species, was destroyed by an alien swarm of unknown identity. Those that survived did so by escaping notice, a small colony deep within a globular star cluster. For hundreds of years they cowered, afraid of doing anything that would draw these Locusts' attention. A deep xenophobia became part of their culture and when they did move into space, they did so with an eye to never being victims again. They began building and fortifying their home system and from there, the nearby worlds and from there, more and more systems, turning their territory into a series of fortresses. Their shift technology didn't develop much; they didn't want to expand beyond their small, safe corner of the universe lest they draw the attention of whoever destroyed the Lett, or other hostile alien powers. When one of the few scouts they did send out detected signals within a few light-years of the star cluster, paranoid panic gripped the Collective and they started arming up even more.

Eventually, contact was made. The Compact had expanded around the star cluster and because the Torvis were the interstellar equivalent of hermit crabs/cone snails, they never realized what was inside the cluster. They sent in an Exploration fleet much like the one that discovered Rally for mapping and resource analysis. The Torvis reacted to this 'invasion' about like you'd think. The Compact responded pretty much how you'd think to. It was a long, bloody grinding siege of a conflict but the Torvis Collective was eventually pacified and their planets and peoples made a protectorate of the Compact, now called Hesitants for their trepidation and excessive caution in exploring the galaxy. There are two main segments of Toletta society: those that prefer the status quo. They remain on their worlds, the Compact fleet protects them (and protects the rest of the galaxy from them, since during their exploration of the star cluster, the Toletta came across a primitive alien species upon which they went full Achuultani) and they can continue being hermit crabs. The other faction is far more xenophobic. They see the Compact's presence as intolerable. Either because they believe the Compact were the Locusts that destroyed the Lett, they believe the Compact may draw the Locusts to them, or they just plain don't like alien dominion of their planets. The Compact has been slowing but steadily grinding the latter down and replacing it with the former.

Trivia

 * It is possible that whatever destroyed the Lett were Naiads, or Parasite.
 * The Toletta exterminated two sapient races before they were discovered by the Compact of Species.