I have an idea for a Slenderman class:
Bombs that inflict blindness and slowness on targets
Limited teleporting, either with a timer or an item
Some kind of damage item or strength
Epic sound effects

The Dragon does not feel like a dragon. It feels like a weak fire mage. A dragon is tanky and destructive, while this class is more of a fireball sniper. It could gain a max health boost or absorption effect. It needs a more spammable attack than its current small fireballs. I suggest spewing the fireballs in a cone for a short distance. It could just have claws or some melee attack instead.