The Medieza have mastered the ability to change other living things into stone. The ray from one of their guns rapidly converts the cellular structure of the target into crystalline minerals. People hit by the beam are locked in place but due to the micro crystalline structure electrical impulses continue to flow thus leaving them fully aware and able to feel and hear all. The change can last indefinably and be reversed whenever the Mediezan chooses. There was one case where a petrified subject was found floating in space, and had been like that for decades.
In addition they were forced to master nanotechnology. Centuries before the K'N'Tara used viral weaponry upon them. Most of their population was wiped out. With their gene pool so reduced they where under dire threat of extinction. They developed the nanites to help them reproduce and to help them fight the K'N'Tara. The Medieza have their nanites flowing through their bodies and with a bite from their fangs can inject them into others. Once the nanites contact foreign DNA they begin to change the victim. Within a week the person bitten will change into an entirely new form.
The new creatures are known as Naghas. Superciliously they resemble the Medieza however they have no arms and normal hair instead of tendrils. They are also all female. Their tails are extremely dexterous thus allowing them to perform many tasks. The Naghas are regarded as a lower and subservient class than the true Mediezans. Naghas perform many jobs that their owners find tedious. In addition they are also a vital part to Mediezan reproduction.
When two or more Mediezans of any gender wish to have children they begin a long ritual. The lovers and a Nagha writhe and caress each other. When the stimulation reaches its climax all the Medieza sink their fangs into the Nagha. The nanites flow through the recipient and begin a change. Within days the Nagha swells and becomes gravid with many eggs. In a few months she will lay these eggs that are a mix of all the donors including the Nagha. Thus the Mediezan's genetic code is strengthened.
The Medieza are not interested in saving other races from K'N'Taran subjugation so much as they are in preventing the K'N'Tara from becoming more powerful. If this means conquering another race preemptively or even destroying it completely then so be it.