Vet Chainaxe Weapon Specialist
 Veteran Build - Warhammer 40k: Darktide 

Weapons - melee weapon should compliment blitz and ranged. Chain axe is easy to learn cause it has literally two light attacks that both come down at the same angle but from different sides, and same for heavies. It's good against armor, so your blitz should really help against hordes hence shredder grenades. Bolt pistol for specials and ranged elites.

Curios - toughness, ability regen, and gunner resist. Revive speed is usually best to get somewhere, but with revive shout you can afford to take the ability regen and not pick it up on your tree to ensure you have revive speed.

Tree:

Toughness replenishment up top, grenade specialisation in the middle with attack speed and field improv for better ammo crates, more nades, better med packs, damage aura because it applies to grenades and your bleeds, revive shout with golden toughness, pick up the extra ammo at the bottom, and head to weapon specialist.

How it works: Your bolt pistol's explosion radius and damage against stunned both apply to your grenades. So do the close damage on ability usage, damage on melee crit, and damage after sprinting and sliding. These buffs also apply to your chainaxe and bolt pistol (if the enemy is close, for the damage when using ability). So basically sprint, slide and get into melee range how you can, when you get the damage on melee crit active, throw a grenade and shout for extra damage on it. Also you now have good enough melee damage to clean up whatever's left with easy to learn combos.