Ta’al Klee are dicks. They are huge, swinging dicks, and you want nothing to do with them.
The Ta’al Klee are the alien species we might call “Greys” -- big heads, hollow eyes, and a predilection for abducting and experimenting on “lesser” species. Pariahs that roam the universe in their Worldships, they continually push at the boundaries of science and have not developed anything close to a sense of “empathy.”
Ta'al Klee do not reproduce biologically. As such, whilst there are still different genders of Ta'al Klee, to an outsider they would not appear substantially different.
As a result of their advanced technology, Ta'al Klee can survive to an indefinite age by upgrading their own biology.