Way of Dark
Doom - Creates a doom portal on the battlefield which detonates after 2 seconds, doing 4 hearts of damage to whoever is inside.
Cast Time: 0.5 seconds
Cooldown: 3 seconds
The location of the doom portal is random. So, enemies never know where it's coming from. However, this means you should be casting it a lot and for that you need a secondary ability based on territory control. Alternatively, you could choose a secondary ability based on enemy movement manipulation. Either way, an ally would be an asset to help corner your opponents into your danger zones.