Sword and Gun? On my mage class?
 Psyker Build - Warhammer 40k: Darktide 

Gameplan for the build is excedingly simplpe, as this is meant to be a very easy to pick up and play build for psyker that focuses on melee.

Covenant Mk VIII Blaze Force Greatsword: Use the light attacks at head height to clear horde, heavy attacks on any chunky targets. In case of shields, your push and follow-up is your go-to. Since criticals will cause Soublaze, when paired with Souldrinker , Wildfire and Perilous Combustion you are guaranteed to remain tough.
Zarona Mk IIa Quickdraw Stub Revolver: Aim it for a bit and direct at any special target you dislike the face of, the crit should be enough to deal with them - and is further enhanced by True Aim.
Smite: While you are mostly picking this skill so that your heavy melee causes enemies attacked to take extra damage, it is a valuable source of crowd control as well.
Disrupt Destiny: Marks enemies so you can focus onto them to keep yourself at a high and heavy level of damage.
Scrier's Gaze: Will quell a huge mark of your peril on use, which when used in combination with Just a Dream and Quietude causes you to regain a huge amoutn of toughness mid battle... Then you pair Purloin Providence, By Crack of Bone (which itself is enhanced by Lightning Speed) and some Empathic Evasion can leave you basically unkillable.

Enjoy destroying the forces of chaos, Sibling!