Dan's build

________________________________________________________________________
How does he not die?
________________________________________________________________________

Gluttony of Elements makes elemental damage heal instead.
If you take a hit (instant damage taken), the gluttony will turn it to instant heal.
If you take damage over time (for example RF), the gluttony will turn it to heal over time.

Lightning Coil makes 30% of physical damage taken from hits be taken as lightning damage instead
-> By lowering lightning resistance by selfcursing with elemental weakness, you increase the lightning damage you take by so much that it overweights the 70% physical damage taken from hits. Gluttony can't heal ES from hits, that's why you see Dan losing his ES.

* Important to note that you cannot convert damage over time effects through "physical damage taken as lightning damage"

While gluttony of elements is on, there are 3 possible outcomes when you take a hit:

1) You lose life (when physical damage taken from hits is higher than elemental taken)
2) You won't lose or gain life (when physical damage taken from hits is equal to elemental damage taken)
3) You gain life (when physical damage taken from hits is LESS than elemental damage taken)

So in an example: You get hit for 1000 physical damage hit, with Coil on and -200% lightning resistance

You take 700 physical damage
You take 300*3 = 900 lightning damage, which heals him as it is elemental damage.
Therefore the outcome of this hit is 200 healing

The game calculates which of the 3 outcomes happens before it is applied to the player's life pool, and thus he stays alive as he is healed more than the physical damage taken from hits would hurt him.

________________________________________________________________________
HOW THE FUCK DOES HE HAVE PERMANENT GLUTTONY???
________________________________________________________________________

He curses himself with temporal chains that has 128% or more curse effect (88% after temp chains' built-in 40% reduced curse effect on players) which makes "40% reduced Effect of Curse against Players" go to 75% (40*1.88 = 75,2, capped at 75%)
This means that any effect that affected by the above has 4 times the duration (1/(1-0.75)=4)
Temporal chains DOES NOT INCREASE THE DURATION OF SOUL GAIN PREVENTION, as it is not an effect on the player but rather a timer for the skill before it can gain more souls.
As of making this pastebin, his tooltip duration for Gluttony is 7,25 seconds, while Soul Gain prevention is 11,62 seconds. So when he uses Gluttony, after soul gain prevention he still has 7,25s * 4 - 11,62s = 17,38 seconds to get enough souls for another use.

The base souls needed for use of gluttony is 100 souls, which is pretty high.
This can be lowered with "reduced soul cost of vaal skills" -modifier, and that is why you need 2x Bloodstained Fossil crafted rapiers that each give 20% reduced soul cost of vaal skills. That means you need 100*0.6= 60 souls for a use of gluttony.
It can then be further lowered by a flask Soul Catcher which has 25% reduced soul cost. By being a pathfinder and having 59% flask effect you can get 25 * 1.59 = 39,75% reduced soul cost of vaal skills.
Those added together you get 79,75% reduced soul cost of vaal skills, which is rounded up to 80%, meaning you only need 20 souls for a use.
Instead of the game reducing the maximum souls needed for the skill, you can now use it 5 times with the original 100 charges, as you only need 20/100 per use. This means you can have a 5 * 29s = 2 minutes and 25 seconds of gluttony uptime for any boss (and you can gain souls by damaging them too)

________________________________________________________________________
How can he start a delve without killing any monster and have gluttony?
________________________________________________________________________

Flesh and Spirit unique gloves give you rampage, and you gain 5 vaal souls on rampage. This means every killstream (15-30-45-70-100, etc) gives you 5 souls. By being a pathfinder (or ascendant pathfinder, but it's far weaker due to not having flask effect!) you can gain flask charges for the Writhing Jar, which drops 2 worms on use. by killing worms you then gain rampage streak and get souls. You let the rampage streak drop to zero after you reach 15 (or 30/45) streak, and repeat to get the streak again. After you get a minimum of 20 souls (1 use when flask is active), you can start a delve. You'd generally want to get at least 40 souls to get 2 uses for safety, though


________________________________________________________________________
How does he get sulphite in HC with 1 life and very little es?
________________________________________________________________________

He respecs to life (only 1 respec point needed) and gets a different gear set and runs through maps with phase run to get sulphite fast, then respecs back to CI for delves again. Here is a good example what happens if he forgets to respec for mapping: https://www.youtube.com/watch?v=qmh5QyeU6-0

________________________________________________________________________
Can it die?
________________________________________________________________________

Yes. Physical degens (that can't be removed) can kill him when he is CI (uber elder is no problem, switch to life and run RF for insane regen) and if his curses are overwritten.

Hexfont nemesis monsters can overwrite his curses, which means he might lose his gluttony if he is not paying attention, but the more dangerous thing is if gets overcursed on elemental weakness. Then if (when) the hexfont curses him with another curse, it removes the newly cast weaker version of elemental weakness, meaning he doesn't have low enough resistance to be healed by PURE PHYSICAL DAMAGE hits. If any hit has any extra elemental damage, it's fine.

Harbinger encounters have blasphemy curses that can overwrite his curses aswell.

He counters this by using Taste of Hate to get extra physical damage taken as elemental instead if his elemental weakness gets overwritten.

However, if he gets nullified (lose flask effect, but gluttony won't be removed as it is an aura, not a buff) AND hexfonted/blasphemied out of his curses, he can die to physical hits.

He cannot be inflicted with corrupted bleed (jewel corruption), but can currently be inflicted with bleed if he is nullified. He can get "bleed cannot be inflicted on you" -corruption on ring, but they are very scarce and hard to come by.

It is possible to set up a permanent immortall call setup on the build to become truly immortal, but it requires a lot more micromanaging and the build is already quite draining to play in delves with all the setting up, and IC can still be nullified regardless.