Robo-Cleric: Max strength healing tank
 Skitarii Build - Warhammer 40k: Darktide 

Overview

The core concept of this build is that by activating and immediately deactivating Advanced Combat Doctrines, you can get back to max charges within 10 seconds, meaning you can permanently maintain max stacks of Advanced Power Management and Sequenced Charge (37.5% strength), along with many other talents. This doesn't take much practice: You quickly hit the ability button, then "1" for melee, and the ability button twice for range. It can be done before starting to fight, or if you notice it's worn off you can easily buff yourself in between swings. 

A lot of the rest of the build follows from that: You'll maintain around max stacks of Residual Current Buffer and Auto-Repair Doctrines, and Moebian Conductor will be consistently on. It's easy to keep max stacks of Redline Capacitors, and Surge-Extension can also be up more than half the time. Retribution Conduit will be consistently 30-35% damage against electrocuted, meaning Branx Mk IV Arc Rifle is extremely valuable. The Branx Mk III Arc Maul is great not just for applying electrocute, but is a weapon that really takes advantage of the huge cleave and stagger buff from the strength, along with having crowd control and great horde-clear. Similarly, Integrated Refraction Emitter helps to partially replace the value of an ability like Voltaic Emitter with emergency CC and anti-range. Gunsmith is extremely useful and possibly lifesaving for the arc rifle, and Uncapped Arrestor is a must-have for a melee-focused build.

But one of the most valuable talents is Voltaic Restoration, which restores 20% toughness to the whole team every 10 sec. You can also spam the ability button to fully restore toughness in a bad situation. With this, and all the other great toughness regen talents, Power Overflow is pretty much as valuable as it possibly can be with this build. We can lean into this with a bit more, and along with other helpful team support like Data Sensor Protocol, this becomes an extremely good support build.

The build fits unintentionally well with the "cleric" archetype: A strong and tanky mace-wielder that casts buffs, heals, and shield. And I guess the arc rifle is some kind of holy bolt or something (I haven't actually played a D&D-based game).

Stat Breakdown

It's hard to overstate how good permanent +37.5% strength is. Since it's multiplicative, it gives massive boosts, while more +damage gets diminishing returns.

With only "damage" talents and blessings, this build has a max of +100% damage against staggered and electrocuted enemies, and +45% against enemies that aren't either. With the strength buff, this jumps to +175% and +99%. A talent that gives +15% damage fairly consistently is pretty solid, so this is like 3.5-5 extra damage talent points.

But this also affects cleave and impact, and is already better that both conditions combined of Adaptive Combat Calibration. But since it's multiplicative with Shockline Breach Protocol, cleave is up to +106%. This is like another 2 talent points in cleave and impact.

Here's a breakdown for toughness regen on ourself:

• Voltaic Restoration gives the team 20% toughness every 10 sec, averaging out to 2%/sec
• Resurgence gives the team roughly 2%/sec in melee combat.
  • It's more complicated, since it's a flat number, so lower toughness means a higher %. Also, it's a bit worse in Havoc, <1.5% at H40
  • Coherency toughness does not get shared by Power Overflow
• The remaining talents give us a fairly consistent average of 10.5%/sec, and a max of 28%/sec in rare situations (like killing an elite with a weakspot crit).

This works out to an average of ~15% toughness regen/sec that's easy to keep up, with rare spikes >30%/sec.

Along with Power Overflow, at max toughness, we're giving a consistent 2+2+(10.5+2 [extra from voltaic restoration on self])*0.25 = 7.13%/sec to all allies. A talent with 3% toughness/sec and high uptime is pretty decent (like Entropic Transfer). Even if we ignore the aura, this is like giving at least 1.5 talents of toughness regen to each ally.

Melee and Ranged

The Munitorum Mk III Shock Maul is also good for this, but the Branx Mk III Arc Maul has better horde-clear and crowd control, which I think is more important for the build. The arc rifle can help with single target damage against carapace and monstrosities.

Technically, you could go for a fast crit weapon and Electro-Strike Conduit, but you'd want at least an extra 2 talent points to do this, and you'd likely have to sacrifice core parts of the build, like Power Overflow. A more standard Advanced Combat Doctrines build would probably be better in that case.

Blitz

This is a very rare time that Integrated Refraction Emitter may actually be better than Artificer Servo-Skull + Medicae Servo-Skull. Servo-skull is always a decent choice, but the anti-range and electric explosion CC is very valuable and cover the weakpoints of the build.

If you charge the arc maul before using the blitz, you can stun and swing quickly to do massive damage though arcs against a tough group, like crushers or ragers.

Curios

I made some compromises here, and there are other options. Having a lot of toughness makes our toughness regen more effective, and it seems like Power Overflow uses flat toughness numbers, so you'll give more toughness to allies (though another 17% doesn't make a big difference, ~0.3%/sec more). IMO, not having +max health feels much less tanky, especially against enemies like bursters, or corruption in general.

Combat ability regen is necessary to ensure we regen the 25% capacitance within 10 sec. Without stacks of Redline Capacitors, even with these perks, it takes about 11 sec, and at max stacks, about 9 sec. This drops significantly when killing enemies, but it's still helpful for better uptime on Advanced Power Management, and it helps keep Surge-Extension uptime over 50%. You can probably drop at least one without much effect though.

Ally revive speed + shield is a decent replacement for the Medicae Servo-Skull. But improving stamina management is also valuable for the build.

Other Alternative Talents

Unfortunately, talents are stretched thin, and the least valuable talents can't be swapped (Power Redistribution Uplink due to low crit, and Binary Ballistics Protocol because it has horrible uptime even on high difficulties).

The cleave from Shockline Breach Protocol feels great, but is not entirely necessary and can be dropped. It may be a good idea to swap Resurgence with Foe-Render Creed, which is likely better in Havoc, and would let us drop that talent and maintain +58% cleave.

It would be hard to drop Threat Detection Imperative since damage reduction is great on the build, but we have a decent amount already, especially from Redline Capacitors. With a servo-skull, this will easily be kept at max stacks automatically, but without, you have to intentionally waste bullets sometimes to maintain stacks. I was finding that even when doing this, I was averaging ~3.5 stacks.

With another talent point, I'd probably take Evasive Servo Recovery, since stamina is a bit lacking. However, Integrated Refraction Emitter can help in bad situations where stamina is a problem.

Voltaic Burst seems like it would be useful as another CC and way to apply electrocute. But it only works when the enemy is staggered by the push, so never against crushers or attacking ragers, which makes it a lot less useful. I haven't tried it, but Overcharge Transfer Lattice might be better for this purpose.