After a relatively easy couple of tamers, you start your last two with a moderate challenge. Grumpy Dark Iron dwarf has all level 17s. Unless you have a really tough composition, you can probably take him at 16, but be prepared to have at least one of them die to his stupid gimmicks.
Comet is a Flying pet. With a Cocoon. He also does Swarm which is where you get attacked by a bunch of little tiny insects that do critter damage and give you the Shattered Defenses debuff. If you have a magic pet, he’s pretty easy. Try and time your hard hitting abilities to avoid Cocoon Strike and keep away from Undead and Aquatic pets.
Ignious is an annoying little Critter. He has this ability called Scorched Earth that hits you with a large amount of Dragonkin damage and changes the weather so that everything is on fire and takes extra Dragonkin damage at the end of each turn. He also has this self heal called Cauterize that heals for half the damage of your last hit. Finally, he has this elemental attack called Burn.
You can put a Beast on him to kill him quickly, an elemental to negate the weather effect, or even an Undead pet as he doesn’t actually do Critter damage. Avoid using Mechanical and Magic pets on him. Also, if your pet still has the Shattered Defenses debuff from the previous pet, it’s a good idea to swap it out until that debuff wears off.
I kind of hate Moltar. He’s not actually that hard to kill, but here you are doing everything right. You’re just slaying the rest of his team. You’re being smart and swapping out your low health pets before they die and then he busts out Magma Wave and all your little backline buddies start getting cooked. He has just enough health that you’re pretty much guaranteed to lose at least one pet to this annoying gimmick.
Moltar also has Conflagrate which does extra damage when your pet is burning, like say when you’re under the effects of Scorched Earth from the previous pet. His other elemental attack, Burn isn’t that annoying and he doesn’t have any heals or damage avoiding abilities. Just kill him quickly and get mildly annoyed with his stupid gimmick.
In Summary, if you have a Mechanical heavy team, this fight might be a problem. Otherwise, you just have to pay attention to match ups and time your attacks to avoid Cocoon Strike or any big heals. Also, slap Moltar once, just because he deserves it.