This was my build for Sanctum, but reading through the patch notes I see no HUGE reason why this build shouldn't work well in 3.21 (RIP arcane surge, as well as regain mana after every 5th cast and 3% of mana as es masteries).

This build focuses on a very spicy interaction that I'm almost certain has been used before, but I can't seem to find any builds using it on PoE ninja. In short, we get our mana costs as high as possible using archmage, and then we take 400% of that mana cost as physical damage with scold's bridle. The hit damage for this is going to be pretty high (6-8k) so we mitigate this with as much phys damage reduction we can find. This couples nicely with Divine Shield, making us regen 3% of that mitigated phys damage as energy shield per second.

Given enough phys damage reduction, the energy shield we get back is a lot more than the amount we take, especially considering that, with corrrupted soul and MoM, 50% of damage taken goes to energy shield, 30% goes to health, and 20% goes to mana. This gives us a super hefty barrier in front of our life and mana pools that can easily regen over 1.5k per second on top of energy shield recoup from Nine Lives and energy shield leech. This gives us a solid alternative to The Agnostic, which I hate using because mana recovery isn't in a great spot.

Note that the majority of energy shield regen comes from Divine Shield, accounting for ~80% of it. So don't feel obligated to get Nine Lives. This build absolutely can work wonders without it, but it is very good on this build if you can afford it.

An important point to make is that, when you take, say 100 damage, we will take 50 es damage, 30 life damage, and 20 mana damage. However, when recoup is taken into account, it considers the full amount of damage taken for each resource pool. This means that 50% life recoup will recoup 50 life even though it only took 30 damage. This goes for mana and energy shield too, making RF actually quite sustainable with enough investment.

In terms of getting the phys damage reduction, we use endurance charges (enduring composure), determination, stubborn student, soul of gruthkul, chaos golem, watcher's eye, and a few notables from glorious vanity (I use Doryani 855 on the top left of the tree, which i figured out using this neat tool).

Cast when damage taken is obviously very useful here. I tried many different setups while playing this build, but I always liked using lvl 20 anomalous shock nova (up to 60% shock) or lvl 1 divergent purifying flame to get consecrated ground everywhere all the time for a bit of damage, curse effect reduction, and health regen.

I used pledge of hands instead of squire + 1h for a long time. It worked very well but i hated how long it makes you stand still, so I crafted a very nice opal wand that I got lucky with while fossil crafting to get supported by crit chance + supported by faster casting + 40% more spell damage.

The only thing I'm on the fence about in this build is the use of arcane cloak. It's a huge damage boost for a brief amount of time, but because we're self-damaging it gets eaten up in maybe 7 or so casts. This is fine for bursting bosses, as that's all you really need at the very most, and it's also good for further mitigating the self damage, but it makes its uptime pretty low compared to regular archmage builds.

Pros:

• Hipster
• Good clear
• Good bossing
• Why are you hitting yourself?

Cons:

• Expensive min-maxing
• Attributes are a pain
• You have to press your mana flask all the time. I get that this is a turn-off for a lot of people, but I didn't feel as though this was a big deal once I got used to it.
• You'd get a lot more dps and survivability out of a different build with the same amount of money. Do this build if you want to spice things up or something, idk.
• Prolly can't do ubers (~15m non-uber dps currently) unless you have great boss mechanics.

PoB: https://pastebin.com/FuC7VkTp

I feel as though I set this us reasonably, without being too much of a PoB warrior. Instead of a 60% shock, i only use 30 here, which I feel as though is easily possible for average bossing. I also don't have sigil of power or convergence on. Frenzy/endurance charge uptime should be 100%, and so should lightning exposure and unnerve because ball lightning hits so fast.

Profile (character name is Sliver_of_Straw): https://www.pathofexile.com/account/view-profile/Dorylian/characters

I might post a video later if people are interested to see my energy shield/health bar/mana pool shoot up and down. The amount of recovery can get to pretty crazy levels.

Let me know any questions/suggestions you might have. I'm sure that some different perspectives could improve what I've managed to make.