Bleed n' Burn Madness Zealot
 Zealot Build - Warhammer 40k: Darktide 

Through FAITH, ye art redeemed

These weird weapons can work well together in the right build. 

Pros: Extremely versatile and fast DPS build where each of your tools is perfectly suited to a different job. You deal a lot of damage quickly and can prevent your team from getting overwhelmed. 

How to play this build:

• Chain Axe IV: Light attack is a single target shred that hits multiple times, staggering lighter enemies and dealing multiple instances of damage. Heavy attack is very fast and has decent cleave. Push attack is very powerful when given buffs and can combo well with heavy attacks. 
  • For the most part you want to stick to lights for single target (even revved/special attacks) and heavies for multi-target. The special will always only hit 1 target. 
• Flamer: Conserve ammo, switch to it when a clearly overwhelming horde shows up, or against a group of armor. Use left click when you need to stagger something, like a dog or an enemy about to hit a teammate. Either use small bursts of ~5-10 ammo at a time then swap to the axe, which will burn trash to death and apply brittleness to anything that lives, or burn the entire mag. 
• Chastise the Wicked: use it to refill toughness if overwhelmed. 
  • In addition to +20% attack speed, Chastise has a hidden benefit where it lowers the armor value of all enemies you hit with melee by 1 category for 3 seconds or until you hit with a melee attack. This is in addition to the increased attack speed for 10 seconds. So Carapace enemies will be dealt damage as if they were flak instead, and flak as if they were unarmored (+carapace etc. still apply).
  • When using Chastise to power up a shredded attack, it will only power up the initial hit, so you actually want to use it immediately after the initial hit, which will then give the rest of the special attack armor piercing, and give your next initial hit armor piercing and crit. This can be enough to 1-shot a crusher with a light special. 
• Throwing Knives: Use them to take out Gunners, trappers, bombers, flamers, snipers, etc, especially when one might try to hit you while you're using your axe special. As tempting as it may be to use them constantly, easy elites and specialists that aren't threatening should be taken out in melee to generate a free knife. Use it to reduce the number of gunners as you run in. It will also pierce the first enemy it hits if they are unarmored or infested and die to the attack, so you can hit a dreg shooter and a bomber with the same knife, but if a dreg bruiser runs in front of it you won't get the bomber. A throwing knife to a rager's head will weaken them and make them easy to kill and get your knife back. 

Other tips

• Against bosses, you want to start with a chain attack and chastise during it, then just use lights for the highest dps. 
• If there's a teammate meleeing a horde, you are usually fine to just join them in melee instead of wasting your flamer ammo and making it hard for them to see. Use the flames when there's Elites and Specialists mixed in with the horde, the team is getting overwhelmed, or if they're coming from an angle no one is already covering. 
• Ping the biggest threat while using the flamer. Your allies may struggle to see high value targets with your flames everywhere. 
• If the team has a Survivalist aura Vet, you shouldn't have to pick up much ammo. If the team doesn't have a Survivalist aura, you will need to be extra conservative with ammo unless there's 2 Psykers. 

Chain Axe IV

Stat Priority: Shredder = Damage = Penetration > Mobility > Defenses

Your heavy attacks have almost no post-attack delay, so you can chain them very fast or follow them up with a push attack or light attack nearly instantly. Your common attack combos are:

Heavy + Push attack + Heavy (repeat)

Heavy + Light (as you slide toward a target)

Heavy + Heavy (conserving stamina). 

Heavy special does slightly more damage than light special but the dps difference is marginal. I would only use it when you're using chastise for the attack since it leaves you vulnerable longer. 

Blessing Combos

There's 3 optimal blessing combos for the Chaxe IV. They come down to personal preference but I put them in order of general effectiveness. Here's a breakdown. 

• Slaughterer + Opportunist: "meta" combo. Slaughterer gives enough power to have reliable hordeclear and to roll through armor once the buff is up. Opportunist gives rending on staggered enemies, which improves both your push attack and your shred attacks (special and light attacks when the enemy is stuck), and will also help greatly against enemies your allies stagger. For shred attacks, Opportunist only increases damage when the enemy is in the 'locked' animation, so it won't help against monstrosities and lights won't give a bonus against unstaggered heavy elites. Opportunist makes the light attacks tear through light and medium elites though. 
• Thunderous + Bloodletter: brittleness results in higher damage for you, and helps your team. It applies 10% per attack that hits. This heavily increases your team's damage against armor and increases their damage against monstrosities/unyielding by about 25%. The special attack counts as only one hit, so without Bloodletter, that means your special attack only applies one stack of thunderous. 
  • Bloodletter has a unique interaction with Thunderous: if Bloodletter is the first source of bleed on an enemy, every tick of bleed will trigger thunderous as long as the chainaxe is out. This means you'll get to max stacks faster and the debuff will continue as the target bleeds, even if you switch targets to a different enemy. 
  • Bleed stacks on special action hit for all other chain weapons suck, but this one is good because it's 16 stacks, which is as high as bleed can go. Each stack increases the damage and duration. The bleed also applies on the very first hit of the combo, so you'll be doing full bleed damage while grinding your axe into their face and the bleed will do more damage due to max brittleness. 
  • This combo only works if Bloodletter is the first source of bleed applied to a target. If bleed is triggered by any other effect before you hit with Bloodletter, the stacks from bloodletter will simply be applied to the previous instance of bleed and thus won't trigger thunderous. However, the reverse is also true. If you apply bleed with bloodletter, then you or someone else adds bleed stacks before the debuff fades entirely, those bleed stacks can still trigger thunderous. 
  • You can cancel a special and switch targets, letting the previous target die from bleed or your team's damage in many situations while you debuff/start killing the next one. Good against light elites like shotgunners. 
  • Throwing knives apply thunderous if the axe is out. 
  • This combo is great for team support.
• Headtaker + Thunderous: Thunderous is less useful without Bloodletter, but its still useful and Headtaker gives you enough power to use the push attack offensively in hordes and increases your boss damage. If you want to debuff a whole pack of armor at once, spam push attack 4 times and watch your team melt them or switch to the flamer real quick. Against bosses do 3 quick lights, then a heavy special and chastise, then spam lights and it will die fast. This combo gives the best boss killing power. 

Chain Axe XII

Will update with more info another time, but all you need to know about Chaxe 12 is that it has crowd clear lights and single target heavies. The normal shred attack is on the heavy, not the light, making it much worse against shooters and light elites but better against hordes and heavy elites. It doesn't benefit as much from attack speed as the IV but damage is much better on it. A chain heavy with thrust and chastise the wicked right after it hits will fuck whatever you hit up. 

Flamer

Crits apply 2 burn stacks instead of 1.

Stat Priority: Burn > Cloud Radius > Ammo = Damage > Mobility

Burn: affects how fast Burn is applied and the max burn stacks that can go on an enemy. at least 78% makes it 16 stacks max. 73% only gives 14 stacks max. 

Cloud Radius: affects flame distance, suppression radius, and how close enemies need to be to the flame to be hit. At max you will apply burn and fire damage to enemies that are within ~1.5 meters of the visible flames. 

Ammo: going from 50 to 80 brings your mag size from 30 to 33. Not a huge difference but every shot counts because of how burn stacks are calculated and the very long reload. 

Blessings

A tier: 

• Blaze Away - Power increase also increases burn damage right as your burn stacks get high enough to be valuable. Encourages you to mag dump which is its only downside. 
• Penetrating Flame - Brittleness makes the flamer not completely useless against Crushers (1.5 mags to kill) and generally boosts its effectiveness everywhere else a bit too. I'm not sure how the brittleness is counted yet, but it doesn't apply the normal debuff and is a separate counter so this lets you stack brittleness above the normal cap of 40%, the only other source of brittleness that does this in the game is Vet's critical hit brittleness talent. You reach the blessing's 20% cap pretty quickly so it can be useful to just fire ~5 ammo worth at some maulers before kiling them with melee to save ammo. 
• Overpressure - blaze away but trades raw power for flexibility. Rewards ammo efficiency over mag-dumping. Recommended to switch to left clicks when low on ammo and let burns stacks do their thing. Keep in mind that blaze away reaches +40% power at half the magazine spent, while this one reaches +25% only once the magazine is empty, a much lower buff on average. Only beats blaze away if you never magdump and frequently shoot ~1/4 of your tank at a time. 
• Everlasting Flame - crits refill your tank. Great synergy with blaze away and crit builds as you can basically fire all of your ammo without reloading, but there's no reason to magdump much longer than a single magazine without Penetrating Flame unless you have an ammo crate to yourself. Very strong only if you are playing with a teammate that reliably applies brittleness to many enemies, such as a Blast Psyker with rending shockwave. 

B Tier

• Fan the Flames - Primary attack has great stagger already without this blessing, but it does let you protect allies better and comes at the cost of damage. Can occasionally save you from being overwhelmed by a horde of armor, but Chastise will do that already. It just turns the weapon into a weird Purgatus with limited ammo. Use with Overpressure. 

C tier: 

• Quickflame - the reload speed buff isn't very high but it's just enough for you to reliably reload in the middle of a horde which can be crucial. 
• Showstopper - 20% chance to explode elites and specialists on kill sounds really cool. In practice it rarely activates and even when it does it mostly just staggers stuff, sending them behind your team and causing trouble rather than doing valuable damage. By the time an elite or specialist is dead, all the chaff that would take meaningful damage or be staggered from it are probably already dead. 

F tier: 

• Inspiring Barrage - you'll refill your toughness by expending a magazine, but you already have Chastise for that. Not worth a blessing slot. 

Momentum vs Martyrdom vs Crit

Up to personal preference. I like Crit for the more reliable cooldown reduction while fighting bosses and hordes, and to provide extra crit for the team. Momentum is also strong for the attack speed and raw damage. Backstabs for cooldown reduction can be easy to get by dodging around enemies if you're proactive.