Fire-based enemies tend to show up on fire-based levels. The thing about fire levels is that, due to this trait, fire-based weapons are ineffective. This makes thematic sense.
What doesn’t make sense is when a (herd? flock?) phlegm of Ice Cubes showed up. Sadly I don’t have pictures of the phlegm, since they converged and tried to kill me if I stayed still long enough to screenshot. But I do have an intrepid individual here.
That happened.
Had I known there would be Ice Cubes, I would have brought along Fireburst Brandish so as to nullify their freeze attack, which is super-annoying at best and deadly at worst. But Fireburst Brandishes are useless on Fire levels…
… except, apparently, in this one case. Unless those Ice Cubes, by merit of being on a Fire Level, are also resistant to fire. Which I actually would be okay with.
I have to say that some of the random level generation is very random.
Spontaneous ∂erivation 
‘m impressed with how much effort you’re putting into collecting and trying the various weapon lines.
Still having trouble with the Jelly King? He shouldn’t be all too difficult if you go in well-equipped.
Stock up on Curse/Fire/Poison/Heals on your way to him. Ignore the little guys and focus on hitting him. Shield against his short spin, and run away and charge when he spins around the room. A calibur or other wide AOE charge is good for this part. Charge up while he spins about, the attack will knock minions away and hit him up to three times, for as much as 500+ or more damage with an upgraded sword. Vile striker (especially solo) can be convenient, although everyone having poison vials is better.
Yeah, equipment is still our problem at this point. We need to seriously level up our swords to actually do even half that much damage each, and we tend to not have much time to level (plus, we all prefer to do the leveling ourselves, and not pay someone else to level our items; just personal preferences).