A contained energy axe can be easily confused with a regular vibro-ax until it's turned on, but it is actually a type of laser ax. Instead of using ultrasonic vibrations to cut, this weapon employs a diatium power cell to generate a magnetically contained energy blade along the ax head's edge when activated.
Although the ax required physical force to deal significant damage, the addition of a centimeter of plasma to its cutting surface enabled it to effortlessly cut through the majority of substances.
The roleplaying sourcebook Knights of Fate released in 2018 by Fantasy Flight Games was the first place the contained energy axe was mentioned.