Equilibrium is your essence, making up the main content of the universe (dark matter). Dark magic can not only suck the lifeforce (Equilibrium) from the caster but also rip a hole in the fabric of the dimension, resulting in a Quantum Purge. That's basically the content of the universe and its respective universes ripping apart, leaving nothing but a white, meaningless void. It also fuels Magic, and Dark magics are fueled by pure, unfiltered Dark Matter, which is why they are so volatile.