Simple damage propagation build with his 3rd chaining damage from enemies into other enemies. Cast 3, cast 4 on top of them, and watch the damage exponentially scale since all enemies are sharing damage with each other. You can keep the dagger fall ability but I find the cast animation a bit long and its a little annoying only having one zone. Subsuming on Thermal Sunder in its place feels a bit more comfortable and lets you stay mobile.

Alternatively you can Subsume over the 1st Ability in favor of a gathering ability such as Coil Horizon or Airburst, to gather enemies before you nuke them with the 3->4 combo. The more enemies you have, the more damage is shared, the faster they die.

Or just don't subsume anything. The kit works well on its own as long as you have high range. Really low investment for the power gained.