I'd incorporate the Metroids, I've been playing Metroid a lot lately. My world has a huge focus on bioengineering. The Metroids wouldn't be made by space bird people but by scientists in a lab. The purpose of them would be to cull a population of an invasive species but things would go south quickly. They'd be the first bioengineered creatures to use completely new genetics rather than just being spliced from multiple different creatures. Because the Metroids are completely a completely new original species no one would foresee the different life cycles. They'd highlight the unpredictability factor of the bioengineering.

So the main character and the group he works with would be tasked to track each one down and eliminate them. This would put the MC in a huge dilemma because they themselves are a bioengineered human species and the sole survivor of the genocide against his kind.

They'd look, behave, and function the same. They'd just have a more earthly origin and be a vehicle for the main characters first big moral dilemma.