Out of all the great character builds possible in Path of Exile, the Burning Discharge build has got to be the most talked about due to its storied development and how much damage it can dish out on the enemy if a high-level character has been decked out with the best Path of Exile items possible. This build has seen quite a few changes throughout the game's transition from open beta to full release, but the main idea has remained mostly the same.
Discharge is an active skill that enables a player, regardless of magical talent, to unleash tons of elemental damage. This is done through the forceful release of a character's built-up charges, whether they're Frenzy Charges, Power Charges, or Endurance Charges gathered in combat. The character build revolves around being able to maximize the damage brought about by this active skill. The best thing about it is that just about any character class can have its own discharge build for farming and leveling.
As it is a build that can be utilized by most classes, the question lies in how charges are gained and how you survive while doing your thing with Discharge. While offense is the reason for getting this build, defense is the foundation upon which this build gains its ground. One of the most popular variations are for the Templar, which makes use of Endurance charges to get things going. Your main goals in passive skills is to get most of what boosts your elemental damage and Endurance charges. You should also go for burning damage since you'll be using fire to turn enemies into ash.
There are tons of variations even to this Templar version of the build due to differing play styles between players. For instance, some may want to take Vaal Pact for the awesome life leech, but some abscond it due to its restriction of healing from flasks. There is also some discussion regarding the taking of Elemental Equilibrium due to its effect of lowering enemy resistances. Some may think that since they'll be one-shotting most enemies anyway that this won't be necessary, but some do prefer taking this passive skill for its great effect that increases how much elemental damage that the enemies take from Discharge.
The good thing with using the Templar is that the Strength/Intelligence hybrid focus makes for a good balance in offense and defense for this build. It would definitely be much easier to keep a Templar alive with this build than with a Witch that requires a bit more vigilance and micromanagement to stay with it. This makes leveling up with this build a bit easier than with others, although the damage is not the most that can be dished out with Discharge as with the Witch. If you do have good PoE items to back it up though, you can give most of them a run for their money.
There are a lot of versions of the Discharge build that you can find information on everywhere. If you want to make farming and leveling more of a breeze, then take upon this fantastic build and see what you can be truly capable of once you hit your full stride.