You 'd take harm to set off your poe currency installation and spells, dealing damage. (You can take a look at this guide for information about how to get the build running. The movie below was made during 2.6, but the manual was updated for 3.0 and still works.)
You could also wear Abberath's Hooves so that your opponents wouldn't need to hit the procedure to be started by you. You walking would bring about the first ignite. If that wasn't enough, you can activate the Elixir of your Doedre, causing damage to yourself and shooting off even your elevated level CWDT setups.
Can this AFK build remain alive? Well, it makes use of Razor of the Seventh Sun to mitigate the damage you deal to your self. Razor heals you for 1 percent of your maximum life each time you provoke an enemy, which offsets the 100 fire damage (after discounts, this number shrinks to under 25). In fact, you are actually healed by it.
You are also a Berserker, so every single time you take 15% of your maximum life in one hit, you leech 100% of the damage you return as life. All of this and Vaal Pact naturally paired, and a life pool that sits around 10,000.
Unfortunately, one significant aspect of the build was in 3.0, which is that ignites do not stack up anymore. You can no longer use Emberwake to enable damage numbers that are incredible. To cancel this, the creator put at a Magma Orb to buy poe chaos orbs setup in the belly, allowing to get a great deal of extra damage, and more ignites to install your CWDT setup. Obviously, when you're using this you are not truly AFK, but you are still able to AFK only nice, your damage will likely only be considerably lower.