The Aelat-Ae

The aelat-ae (singular aelato-ae) are fugitives from galactic justice. Their ancestors were the masters of a cruel authoritarian regime that held psionic dominion over dozens of "lesser" species, including their genetic cousins the aelat-prime (now flourishing in the wreckage of the old empire). When the other great civilizations of the galaxy finally banded together as the Retribution Legion and brought down the hierarchy, the handful of aelat-ae that escaped, mostly dissidents and hangers-on with little stock in governance, fled aboard catapult ships, fast, barely-controlled vessels designed for those with no direction more specific than "away from here". Complicit or not, all aelat-ae were as guilty as one another under galactic law, and were to be hunted down and brought to justice.
One catapult ship made its crash-landing on a backwater planet named Colwood, and the burgeoning human colony there gave the dozen aelat-ae aboard the perfect cover. Using their psychic powers to mask their genetic signatures and disguise their bodies, they have eked out a living on Colwood for a century and a half, but their comfortable exile is now threatened. One of their number has died. His disguise wore off immediately, and the humans who discovered him, who had, until then, thought themselves alone in the galaxy, took the body away for examination. It's now being kept under maximum security somewhere on Colwood, ready to be taken to Earth for examination, and its discovery is the top story on every news channel across human space.
Now that he's dead, though, there is an unmasked aelato-ae genetic signature shining out bright and clear from Colwood, and it's only a matter of time before the much-diminished but still active Retribution Legion finds it. The aelat-ae will purged, but, worse, the Legion's paranoid leaders will deem humankind guilty by association, and punish them appropriately. In a week's time, the corpse will leave Colwood for Earth, and it will be almost impossible to track it down or quell the signal. Before that happens, the eleven remaining aelat-ae and the handful of human allies they've managed to enlist must find, steal, and destroy the body, ideally without letting Colwood's population know that they're harbouring live galactic fugitives.
Simple enough, right?

Basic Information

Anatomy

Aelat-ae are still physically mostly identical to the aelat-prime they once oppressed, distinguished mainly by the psionic potential that first united them as a superclass above their brethren. In their natural forms, they are roughly spherical, dull purple creatures, about three feet in diameter, with six multi-jointed, interchangeable limbs that serve as both arms and legs, each ending in four spindly digits. They can mimic the human form surprisingly well by psychically altering observers' perception, though their handshakes feel... wrong.

Additional Information

Perception and Sensory Capabilities

The aelat-ae do retain the multisensory organs of the aelat-prime, but generations of inbreeding to maximise psionic potential have rendered these organs vestigial and useless; they now perceive the world entirely psionically, sometimes by borrowing the senses of other beings.