Had reports of some extreme amounts of casters spawning, so I added in a maximum spawn counter for them, its currently set to 8.
The way the enemy spawn system works is a weighted list so normally they shouldn't build up but if they don't get killed I've seen dozens of casters all casting fireballs and its quite hard to deal with so I'm hoping this evens things out a bit. I can always bump that number up or remove it completely.
I'm open to any thoughts/idea in regards to that.