After referencing some builds here for ideas, this is what I came up with for my own.

• A bit higher duration (more dps), less efficiency (offset by arcane energize), higher strength (because why not).

I've used this in sorties and other high lvl survival missions and it holds up pretty well.

Remember to keep up Immolation (2) for the 90% damage reduction, and only turn it off for energy management. It's quite easy and fast to get the meter full again. Your Fire Blast (3) is really good for CC since it strips armor and knocks enemies back. Then of course we have the explody murder comet aka Inferno for doing all the AoE killing. Thanks to [Exothermic]'s 15% drop chance for energy orbs + arcane energize you'll be all set. If you really want you can equip [Dethcube Prime] with [Energy Generator] augment for even more energy orb drops, but it's hardly necessary. Enjoy :)