"With this enchantment, the necromancer (you) has mastered a dark ritual enabling him to reanimate the largest of all animals. The former elephant is preserved in a state of perpetual decay by a revenant mage (not you) who constantly fuels the Behemoth with energies from the Underworld. The most important part of the reanimation ritual is the binding of the mage's (not necromancers) spirit to the Behemoth. This direct spiritual control of the Behemoth gives it high magical resistance. As all of the mage's energies are used in controlling and preserving the beast, he or she is unable to cast spells."

Seems pretty simple if you take a minute to read it instead of just picking out key words like "mage"