Passive:
[Ember] receives a 5% ability strength increase for every enemy within 50m that is engulfed in flames aka has flame proc.

Abilities:
Roar
Immolation
Fire Blast
Inferno w/ [Exothermic] Augment

I replaced [Ember]'s 1st ability to allow for more damage on her others. Since I'm on console and [Hate] the way this kind of ability needs to be used, I went with something I can hit then forget about. At the same time, once your flames really start going, I feel you won't be hitting her first ability as often. Even though the build has slightly negative duration, you still get around 28.5s of Roar, so not much of a loss, especially since it costs around 33 energy.

For Immolation and Inferno, her 2nd and 4th abilities, I [Primed Continuity] to balance out the maxed [Fleeting Expertise] since the efficiency seems to have a better effect of reducing the cost for these two abilities. Also, since [Ember] is constantly using energy I felt that Arcane Energize and Arcane Eruption can help with energy management and crowd control.

Fire Blast is an amazing ability that I didn't realize existed until recently when I decided to play her again. She can strip 100% of the enemy's armor if her gauge is maxed out upon cast, which lets everything else she does do damage straight to the enemy's HP. She's also got great crowd control since the ability also knocks enemies down.

I've been running her with [Ignis Wraith] since her passive and [Growing Power] work so well together. Her passive is incredible and can make her soar to even greater heights easily, for example: Light 5 enemies on fire with [Ignis], you get a bonus of 25 from [Growing Power] and from her passive. BAM, instantly at 200%+ power strength. Overall, I am very happy with this build and look forward to seeing how others can improve it.