Little Bit

Seeing that the MCOMs were working, the others also took their own out. Opening the map, they found their location. There was a very big red name on it, as well as various warnings of danger. 

"The Magic Decay Valley..." Claus felt a chill on his back when he read the name.

Magic Energy could be used in many forms. For Maguses and Familiars, you had natural Magic Energy with various levels for their training. For big vehicles like aircraft, ships, etc, everyone would use Magic Fusion Fuel Rods, which are great for big bursts of power but terrible and potentially harmful for any Magus or Familiar to use in their leveling process. 

Then, you had what people considered waste: Magic Energy used in various types of processes that became too contaminated and lost all their power for further use. If that was all, it wouldn't be a problem, though. The issue was that this kind of magic energy waste was also a poison.