Venjix started out as a computer virus created by Dr. K that infiltrated all the world's power and took over. Venjix can create endless armies of robotic soldiers and he appears to his generals in the form of a red light bulb. He later downloads himself into a generation 14 attackbot that Shifter designed. He pilots a special green drone and can make new robots of the same model to download himself into. Venjix made a newer and more powerful model, but he wasn't fully downloaded into it because he was in a rush and was defeated. He decided not to use the model again. He used a new model later on, using old parts of Shifter. He activated many Hybrids within Corinth and took over the control tower. He then destroyed the lab and took the biofield information, being able to delete Gem and Gemma. Dr. K and a newly restored Tenaya were able to tap a virus into Venjix's main computer and override his ability to delete Rangers. Venjix was physically destroyed with the control tower falling on him. In the finale, it was alluded to that a part of the Venjix virus was still inside the RPM Morphers, that were locked away in a case by Dr. K.
It's possible that he'll return in the future.
Venjix has some similarities with Skynet, as both are software that both took over machines and the world, which than made an army of machines to do so. However, their origins are completely different, whereas Venjix is came from a computer virus, Skynet originally came from artificial intelligence system.