Alexander Maxwell Nox was born to Arthur Rutherford Nox and Katerina Ticacek Nox on February 25, 2685. He worked as a research scientist for Humbert Labs on his homeworld Gaea, the Frontier's leading manufacturer of pesticide gases. With a glut of pesticides needed to protect the growing Frontier colonies’ crops, Humbert Labs was constantly on the hunt for better and stronger formulas. Nox was one of their brightest scientists and worked day and night developing new gases. But to make sure they worked, he needed to test them on more than just inert tissue: he needed something living. As he toiled in secret, Nox began to see the beauty in his creations and their ability to destroy anything they touched. But the head of Humbert Labs, Dr. Franklin Humbert, soon discovered his gruesome experiments, and their confrontation ended with the lab in flames and its chief dead. Today, Nox is missing and presumed deceased, his supposed body found and identified by his mother, charred and beyond recognition. 10 years later, Caustic now finds new test subjects in the Apex Games, where he puts his gaseous creations to work and observes their effects with great interest.