As for Psykers, a special tip... as soon as you unlock that skill, use Warp Speed to get a much higher firing rate on your weapons, which will allow you to dispatch those trashmobs much more quickly while also managing your warp heat more efficiently, so that when bigger mobs show up, you can unleash your skills without having to worry about warp anomalies.

I failed the mission the first time as a melee crusader and completed it the 2nd time.

What I did different the 2nd time was I placed the mines 10 meters from the tech priest and focused the enemies coming in the other directions, I stayed at least 5 meters close to the priest to assure nothing got to close.

When I got the turrets I placed them close to the barricades and the left side of the priest and the back and I used the jump ability and the charge with greater axe to catch up to any mobs coming in. I used grenades if I was on CD and basically if no mobs were around I would go to the spawn entries and kill about 5 or so then run to the next spawn entry and kill a few more run back to the center and kill off the rest.

Good luck and hope you complete/d it!

Fight on brothers!

Failed the first time with Crusader since I didn't know what to expect. Got it 2nd try. Use the jump armor and melee, stay close and don't chase mobs till you thin them out. Do not deploy turret too far so they can provide overlapping fire. but not too close to the tech priest so AOE attack against them won't cause him damage.  Use Grenades against large mobs. TP have over 3K HP left at then end.

Just did it with an Assassin with the sword that allows jump attacks. no problem.

Emperor bless you !

Wipe out all the entire Pts spent on Close Combat bonuses and change it ALL into Speed and Movement instead. Lol.

Please, anyone else with a Crusader played through this Mission. Please tune in.

How on earth are you gonna make it in time wave after wave? Your Tech Priest doesn´t take much damage either before he collapses. And so many mobs are coming from all sides.

Am playing Crusader (Melee) and having a huge and hard time trying to go through this Mission, but now I need some serious/good tips on how to actually make it through.

Could it be an idea to bring a Gravgun to this Mission? Could that be a weapon that could actually give me enough time to deal with all the other mobs coming from the other sides?

Any tips, please.

Meaning I could still kill the mobs reasonably quickly, but there were just too many mobs all at once for me to target them all at once... especially since they nerfed Witchfire and doubled its cooldown.

On Story, it was a walk in the park, more or less... main difference being the mobs not doing any damage to me anymore, hardly broke through the shield, so I could nonstop attack and I didn't have to watch my Warp Heat that much either since I could use my LMB warp blast more often without needing "the big guns" all the time.

Strategy-wise though, I did it differently from you -- depending on what mob group was thrown at me, I sometimes went towards them so much that I could kill them right in the doorway through which they were coming, just so that ranged mobs wouldn't even get in range of the priest, and it sometimes helped to not wait until they were in range of me standing next to the priest, because by then two more groups would be almost in range.

I do have the perk selected that gives me +25% movement speed at green supression, so that might be something worth looking into for you as well.

Here's my build with then PR351 like I said:

Psyker Rank 12 (then), 2x Warp Rod, Void Shield Generator, Skills chosen:
LMB/RMB from Dual Warp Rods like you, plus Fiery Form, Molten Beam, Spontaneous Combustion.
On Story Mode, it wasn't really a problem anymore... like I said, Tech Priest still lost almost 50% of Health, but nonetheless made it first try on Story... hard mode though, my usual level, virtually unbeatable.

Setting to Story difficulty works, yeah, but that just reinforces the point that it's badly balanced, given that at Power Level 351 I had to dial it back to Story 210 to get through, when otherwise I handle PL 400/450 missions quite handily.

Playing as an Assassin (both sniper and mele) and sometimes the choice of weapons can have quite incredible effects.

Had 1 or 2 missions where I struggled to pass unsuccessfully, than changed just 1 or 2 items and then pufff all was easy.

1. Set to Story-Mode

2. Place the guns on the corners of the yellow square on the ground (far enough from the Priest)

3. Concentrate your attacks on the range opponents. 

4. Kill the Elites, bevor they destroy the guns or break through to the priest

Re-tried the mission on Story Difficulty instead of Hard Mode, and I managed to complete it -- however even then, the Tech Priest still lost almost 50% of health, again due to me being a) overwhelmed from all sides from Wave 4 onwards, and b) the World Skill Turrets dying, plus c) champion mobs with their huge AoEs hitting the priest.

I don't stand near the Priest, which means trash mobs swarm the priest and kill him almost instantly.

Turrets get destroyed almost as fast as I can spawn them... this is definitely not balanced correctly, given how well I've been able to handle any other defend the base-type mission on Hard so far.