The Seraph of Flame - Righteous Purgation Build
 Zealot Build - Warhammer 40k: Darktide 

Crit Focused support build - "Lend me your wrath, lend me your hate, lend me your fire!" — Saint Celestine

She's died in this war more times than most soldiers have fought in it, and every time, she gets back up.

• Seraph's Tac Axe - Light spam is kinda busted on a crit build as it can even churn through armour when paired with Fury of the Faithful. I recommend an auto swing mod if on PC; mix in defensive pushes or special attacks to stun ragers, then just light spam most threats. Scourge will proc like crazy, allowing you to bleed enemies and keep cooldowns super low, and other nodes such as Sustained Assault and Enduring Faith have crazy high uptime. 
• Fury of the Faithful - Here to get us moving like an avenging angel through charges and attack speed. We can even churn through armour quite well thanks to the rending. Scourge Fire and Fury also not only allow for extra fire stacks, as a seraph demands, but that target takes an extra 30% damage from your righteous axe!
• Purgatus Flamer -  For the unwashed mass armoured hordes and, most importantly, bosses. Primary attack is great for stagger or to proc Penetrating Flame into crushers, with the secondary mode for the massive hordes. Burning away corruption is as much doctrine as it is tactic with this build. Anoint in Blood fits perfectly with this aggressive style, so get close to burn those bosses with Purifying Hatred. Everlasting Flame may seem tempting, but the lack of total ammo on the flamer makes it overkill; more debuffs and damage are preferred to having to do a reload occasionally. Great for mixed hordes with crushers due to Penetrating Flame.
• The Reverent Saint (Shield of Contempt) - Very good support utility; procs only on health damage, so saves us when running into a bad spot with gunners paired with Wait in Line. Also very good if team members are down, as it gives more time for revives with Providence. 
• The Blades of Faith  - The objectively best choice, allows for instant swaps to flamer animation cancels and dealing with specials at range. However, the Immolation Grenade talks to us like the green goblin mask; more fire makes the seraph a happy gall!