exhaustion limit ?

is there a limit to how exhausted you can be ?
or you can go all the way to 0 energy.

I would think you could screw yourself all the way down to 0.

Absolutely, especially with skills like Gale that cost 5 but also cause exhaustion.

You can, in fact, go down to 0 energy.

I've done it before to myself on a big boss who I had to keep hitting with Gale-- from 80 to 0 in just a few minutes, so be careful of using cheap spells that cost Exhaustion.