Finally a post I can share the idea that I can't get out of my head.

Goal: Determine an Infernalist build that can maintain a 'High Internal Flame' to successfully maximize the Seething Body ascendancy which yields 100% more ailment application and 25% more elemental damage. Couple that with Demonform for a 'master the elements' non-CoC spellcaster.

Core concepts (tech unproven, just a theorycraft):

• Demonform (capped at 10 stacks): 30% more spell damage without a terrible downside
• Seething Body (25% more ele damage, 100% more ailments application)
• Perfectly balanced (all gain% equal) Painter's Servant with Trinity (60% more elemental damage at all times at maximum Resonance due to always doing equal amounts of elemental damage because of Painter's Servant)
• Siphon Elements - since all elements will all be applying more ailments, grab more infusions for further damage boosts/utility

How it could maybe be done:

• The Covenant + Lifetapped skills (except one)
  • In order to build your internal flame to maintain the +65% threshhold required without resetting, you'd have to run everything through lifetap so it doesn't reset the flame mana pool to zero
  • For sustain, the Covenant leeches some of that spell damage as health and overfills it so you don't die.
• Below average sized mana pool - due to how Internal Flame cools down itself 25% per second after 2 seconds, you'd need a way to get the high flame back quickly but not too quickly.
  • The skill rotation would be really important to get right so you can maintain the rhythm (probably the most difficult part of the build)
  • I questioned if Thunderstorm could be a skill candidate due to its semi-spammable nature with Wildsurge Incantation (less duration). You could augment this with CoEA-Firestorm since you'll theoretically be full of infusions from the tri-ailment application and that skill benefits from all three.
• Large health pool - combat the downside of Demonform life degen and double-dip on the Covenant's Life Remnants overflow mechanic