Dark Storms is a very nice and basic skill, including a very nice condition interaction.
Imbalance of Nature is a very good supportative spell, while also prepares you to cast
Dark Storms.
Boon of the Feebleminded is the skill, I find a bit overpowered. You basically permit a hero not to attack, nor to cast spells or punish him not to be able to cast spells. That would be alright, I would still cast a spell than go attacking, but I get damaged everytime which forces me not to do anything.
Basically for the Ultimate we require a spell, that either causes mulitple conditions, or has something to do with conditions. I would go for this:
Level 6 Ultimate
Ability Name
- Activateable - Whenever a unit nearby isn't attacking, he will have all his already applied conditions extended by 1/2/3 seconds, and will be dealt 25/50/75 damage.
Boon of the Feebleminded will have units not attacking, extending their conditions. But if an enemy is fleeing or simply moving, even that will trigger the spell, thus creating a nice scenario for you to unleash
Dark Storms. That's my best, sorry.