Psyker
12-24% Rending on Enemy Weak Spot Hit for 3.5s. Stacks 5 times.
12.5-20% Critical Chance for 6s on successful Dodge.
Enemy gains +3 Stacks of Soulblaze on Critical Hit.
2 Shots on Critical Hit. 2-5% Ranged Crit Chance.
This build is what is use in T5 and above it's great with stunning hordes and throwing them on the ground to let you or preferably you team clear them there are very few things immune to your lightning and with a good team nothing can get close to you
As I have so very few things are immune to your lightning they are beast of nurgle, plague orgyn, chaos spawn, demonhost assassination bosses and any enemies that have the blessing of nurgle which is a modifier in higher tier content (the blessed enemies will be glowing green you lighting does not stun them so be careful in those type of mission and make sure you or your team get rid of them)
Weapon:You have good options on Psyker for melee and you primary for melee I suggest either the assault chainsword good against multiple enemies and great for single target it's special ability let's you activate it which is amazing for cleaver single targets the only things that will take a while to kills are mauler and obviously crushers.
Dueling mark 4 has a lot of dodges great for getting out of a tight situation it's heavy is great for single target and it's light is ok for hordes not as good as other weapons but don't underestimate it
Blaze for 5 or 2 is also a good option it can reduce peril when holding your reload and itd special builds peril but it does more damage.
Staffs are purely up to you I don't suggest guns as
your taking ammo away from your team who haves better weapon and builds for them and staffs just have more variety I use the purgatus because one of the talent's works brilliantly with it but you have the surge staff for dealing with close to median range single targets voids for medium to long range trauma is good for hordes and throwing every single enemy in the game to the floor these all are amazing weapons in the game.
Curios: what have suggested is what I believe to be the best you can change the corruption resistance to sniper resistance but corruption ( I might be wrong) gives resistance to any small enemies hit ( what I mean is they give corruption when they hit you with a melee) grimours nurgle spit and the build up from demonhost but from what I've heard from other people they struggle more on snipers then melee so it depends on how fast your reaction time is.
Playstyle: The most optimal way I play smite Psyker is to find a one way where no enemies can get out of you range or behind you and keep everything still for your team to clean out you range is pretty decent and smite is like a cone you don't have to be staring directly at a enemy.if you can't find a one way go to a corner or turn around occasionally you can keep stunning while not looking but don't do it for to long if enemies do come from behind obviously tell your team and let go of your smite when you do this it throws them to the ground (this only works on the weaker enemies other will be staggered for a short amount of time) it's directional when you throw the so if your looking at them you will throw them backwards doing it while facing the opposite direction of them throws them forward and so on you should pretty much be using this anytime a horde or a massive group of elites or specialist are coming for you not only that but if you can get one gunner you can most likely get them all with Smite letting your team deal with them without getting shot at most of the times. If times are tough your recharging and they are getting to close pull out your sword and block with this build it will use peril instead of stamina so you can push the back with losing your block and possibly your life.
You can change a few things around like warp siphon to empowered psionics for more horde killing then getting your shield back faster and could change stamina to whatever you like I suggest it because of how little Psyker has so you can push as much and with this build your block uses peril not stamina which is huge in surviving against most things even demonhost can't get you as long as you are smart and careful
That is everything I can really cover smite is very helpful and I suggest using it to support your team it help me and my team survive situations I wouldn't be able to without it and I truly hope you enjoy it I understand it won't be for everyone so I will be making more builds later on to hopefully help you find a way you like playing