@vichn
Well, DH tends to 'steal' the 40k psyker disciplines.
The Angels of Death book brought out a handful of generic 'new' disciplines for Space Marines (because #Space Marines Get Everything, Why Aren't You Playing Space Marines?). Chaos marines got a matching set of disciplines (with the same powers renamed, so Geokinesis discipline became Geomortis discipline for example).
These were:
Technomancy - psychic 'attunement' to technology that let you heal/disable vehicles, weapons and so on. Subvert Machine - Does exactly what it says on the tin. See that turret mount on your tank? I'm firing it for a change. Blessing of the Machine - Your gun is more better now! Improves accuracy/reliability/whatever Machine Curse - Essentially a psychic haywire grenade Reforge - Fix the broken machine. Psychic healing for stuff with machine or vehicle traits. Warpmetal Armour - temporarily makes you turn into Colossus from X-men. Dodgy Russian accent optional. Fury Of Mars - Another haywire attack, this time a relatively long-ranged 'lance' of power that can skewer multiple targets. Machine Flense - Your vehicle's armour explodes off it as a cloud of fast-flying razor blades, which is very bad for both the tank and anyone sheltering behind it! Geokinesis - Essentially allowing you to move around the earth, rock, buildings, etc. Pretty much a highly specific telekinesis, I guess Chasm - 'instant bottomless pit' Earth Blood - healing power, drawing on the planet's vitality Scorched Earth - 'instant mini-volcano' Landquake - 'instant earthquake' centred on you that knocks everyone prone Phase Form - give a nearby ally/group of allies the phase trait. Warp Quake - 'instant earthquake' centred on a nearby structure to make it collapse Shifting Worldscape - 'this building now over here, that one over there' - possibly rearranging the scenery like in Doctor Strange? Librarius - a 'weird stuff' discipline that didn't really focus on any one theme other than a place to put famous power names that weren't currently in the game (like Null Zone). The Emperor's Wrath - 'Psychic Hadoken!' Veil of Time - 'tactical prescience' for the psyker, making him and friends better able to dodge. Fury Of The Ancients - 'have a psychic monster image to the face' ranged attack. Psychic Fortress - Resistance to incoming psychic attacks Might Of Heroes - Generic 'make psyker stronger, faster, better' power. Psychic Scourge - A psychic attack designed to kill other psykers. Null Zone - a sort of psychically-created-untouchable-bubble ('I'm holding the warp at bay') that weakens with daemonic auras and psychic shields. Fulmination - the 'throw lightning around' discipline - i.e. the name for the discipline you're creating here. Electrosurge - Have many lightnings to the face! Essentially a pair of sawn-off heavy bolters in power - lower pen but much higher rate of fire than Smite (psychic barrage?) Electroshield - the classic fantasy 'lightning shield' Electropulse - A nova (area effect centred on you). Has a haywire effect, but shocking is frankly more appropriate. Lightning Arc - Same power as Electrosurge but lower rate of fire (D6 rather than 6) - potentially 'chains' from target to target, though (use the autofire rules for applying extra hits, I guess) Fists Of Lightning - Electric Punch! Bonus strength, attacks, and extra electrical discharge damage whenever you hit someone (whether you hurt them or not). Magnetokinesis - 'throws' a unit or vehicle around Electrodisplacement - teleport, but pointedly 'swaps' one individual or group with another rather than just teleporting you to empty space.  
I'd recommend matching the 'existing' titles and discipline name.
Anyway;  the powers you've posted
Hmm.
It's pretty awful, isn't it? 1D10+PR is going to be notably less than just thumping someone with a club unless you're at least Psy rating 4, or are prepared to push the power (as a psychic power it won't automatically add strength bonus unless you tell it to). Yes, all right, shocking, but compare this to thwacking someone with a shock maul.
I would make this Fists Of Lightning - I'd recommend adding PR to damage (and maybe pen) of unarmed attacks, and granting them shocking, plus maybe adding some sort of 'extra-damage-if-you-hit' mechanic a la Toxic (X) or Force.
Damage is respectable for a ranged power (PR3 makes it equivalent to a lasgun) with a small-but-respectable pen value and the Barrage subtype so a decent psyker can throw out a lot of shots. Fair enough. Electrosurge? Might even suggest making it a bit weaker and upgrading it to a Psychic Storm (full auto analogue)
Definitely Electroshield. I'm not sure about the oddly specific provisions for the armour bonus; if it works against shrapnel from grenades, for example, why wouldn't it stop buckshot from a shotgun? I'd make it work against any 'solid object' (so any Solid Projectile, Primitive, Bolt, or Launcher) weapon - by comparison, if I can still see you, and you can still see me, a lasbolt should hit you just fine.
The range seems a bit much. If it's a shield, I'd have it be centred on you, and PR metres is probably enough.
By all means give it a haywire effect - but as listed it's better than haywire, which seems wrong, especially since you can throw the effect 20 or 30 metres away.
Interesting ability. I'm more than happy to see a Fulmination 'stealth' power (suggest stealing The Shrouding from the Daemonhunter sourcebook?) but casually adding a shocking melee attack with the Warp Weapon trait (ignores all armour, up to and including best craftsmanship Heavy Power Armour) is NOT something you can add as a 'side bonus'. No Fulmination equivalent, so keep the name.
Shouldn't that be 'static trap'?
Centre it on yourself and it's Electropulse. It seems a fairly convoluted ability given that it's not all that useful; it's a WP-10 ability to manifest, and unless you just manifest it directly on top of someone (which, lets be honest, is what you'd do) it isn't all that great - it's visible on the round it appears, and maintaining it needs a WP-10 check every turn and you to stay within 20 or 30 metres. I'd just stick with a one-turn psychic nova centred on you.
Magnetokinesis. works in theory, but unless you can move the target (other than just levitating it a couple of metres up and holding it there) it's not massively useful. Rather than putting a radius on it, I'd give it a 'weight limit' related to the PR - so a novice can lift a few metal objects whilst a Primaris can play Magneto and throw groundcars and light armoured vehicles around.
Lightning Arc. A Psychic Blast for 'arcing between nearby targets' is a decent match in mechanics.
 
This is seriously nasty - 1D10+7 pen 3 is 'light support weapon' territory, which is nasty, but you're delivering it to potentially a huge area - 6 metres or more across. I'd probably model this with a Psychic Barrage, though, if it's going to be this powerful - so you'll get hits but not too many.
Also - slightly weird fixed damage - meaning that initially it's massively better than lightning bolts but could subsequently end up being worse. I'd probably make it 2D10+PR - more potential damage, more chances for righteous fury, but still scaling with the psyker's power.
Electrodisplacement. I'm not sure I understand this as listed - you only talk about creating one 'gate', and since it's going into the immaterium, it having a haywire effect is the least of your worries if you're caught in it!
I think the 40k 'swap places with someone you can see' is a nice, interesting effect.
For the 'ultimate power', it's not actually all that powerful, is it? What do I get from this that I don't get from Lightning (aside from tazering myself with accumulated power)?
Ultimately, not sure this one is needed - you've got a 'zap' power, a 'zapzapzap' power, and a 'ka-zap' area power; given DH's nice mechanic of scaling range and damage with the power and attitude of the caster, you don't really need a fourth unless it does something specific (draining life energy feels like it should help me heal wounds and/or recover fatigue?)
 
Other observation; None of your powers reference one another as prerequisites. The way DH2 works is that one power (in this case I guess Jolted Touch/Fists Of Lightning) is the 'entry level' power and all the others follow on in a tree. Would suggest:
Fists Of Lightning - Electroshield - Electropulse - Magnetokinesis/Electromagnetic Cloak ('field effects' tree)
I
Electrosurge
I  
Lightning Arc
I
Electrodisplacement
('bolt effects' tree)

Anyone to help me? 

Just noticed a typo (unless its a pun I don't get) on your Litany Generator:
"Without  the  Pmnisiah,  there  is  nothing,…  And  we  would  have  no  purpose."

1. It's likely the Logi Daemonis from CA 23
2. No. Again their character concept isn't canonical.
3. Yes, that is literally what a daemonhost is, Implantation or no.

Sister Cat said:
... (depending on his relative puritanism) ...

"Relative Puritanism"...
is this more similiar to
"gentle violation", "reasonably radical" or to  "benevolent abuse"?
 

Realm of Chaos: Slaves to Darkness was a progenitor to the 40k lines (from WFRP2).
Try the Metamorphica
http://www.drivethrurpg.com/product/115703/The-Metamorphica-Classic-Edition?src=hottest_filtered

Hi everyone.

If anyone is interested, I found a non-DH expanded mutation table.
http://www.slackratchet.com/rough2.htm

And that's why the party disbanded... 
 
I'm not gonna die
I'm not gonna die
I'm not gonna die
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAgh!!!

 
Would be awesome tough.
 

Alcoholic sniper. Not my idea, but somebody over on the Only War forum had rolled up a guard sniper with the alcoholism drawback. And I think that's just briljant.
"Only two ways to look at the world, trough the bottom of a bottle of amasec, or trough the scope of my long las."
"I had the man dead in my sights. I aimed for the right head and missed. I should have aimed for the left one. Seeing double sucks when you are on a mission."
"The worst part of delerium tremmes is seeing horrible monsters come trough the walls.  Not that I'm scared or anything. It's just hard to tell the real chaos daemons from the alcohol induced ones."
"Worst mission ever? Fighting noise marines when you have a hangover."
 

Nipple rings (or rings in general) or filed teeth for Slaanesh cultists. Implanted horns for Khornates. Adherents of Nurgle could perhaps use syringes to implant their skin with pustules, or inject themselves with various toxins in general. For followers of Tzeentch, perhaps talon-like ceramite fingernails or blue "reptile eye" contact lenses.
In general, you just need to look at either the daemons or the practices of the cults, and then extrapolate what and how someone could emulate / pay homage to them.
Of course, most things like these are fairly obvious, and so may be encountered openly only in places where the Emperor's light does not reach (underhive, non-Imperial worlds). However, I'm sure some could be passed off as merely a local quirk, to be recognised only by fellow cultists. Elsewhere, such displays of affiliation would likely be far more muted, or perhaps concealed under clothing.

Very succinctly put.
Slaanesh: The pursuit of new more extreme sensation at all cost.
Tzeentch: The use of and pursuit of arcane knowledge for personal benefit.
Khorne: The enactment of brutal violence for personal glory (glory here being nebulous).
Nurgle: The pursuit of seeing the great cycle of life, death, and rebirth/change continued and furthered.

Oh, my, this is what I was looking for. Thanks!

Sort of, yeah. Ultimately, any and all actions are meaningless unless they affect the psyche of either the perpetrator or a victim -- because the Warp functions based on and reacts to thought and emotion, not because of some physical thing on the material plane. Flesh or steel matter naught, it is the mind that is both sustenance and manipulator of the Immaterium, including its creatures. As such, faith truly is one's best shield, as aptly demonstrated by the records of the Sisters of Battle. Or, to quote a Thought for the Day: "Ignorance is bliss."
Taking the above example, burning an NPC in the name of the Emperor would leave the attacker unharmed as they are convinced by the righteousness of their action. On the other hand, the victim may well fuel the power of the Dark Gods because of the fear or hatred they feel at the moment, or because his or her death makes others (friends, relatives) feel despair or hatred. Of course, such minutiae of Warp cosmology would be utterly unknown to the characters themselves, unless they are an extremely well-versed Inquisitor in possession of forbidden knowledge.
Of course, the same action may still yield an emotional response later on if a character re-evaluates it and comes to the conclusion that they have committed a wrong -- triggering a crisis of faith.

i would say you overthink things too much. corruption points is exactly that. your downward path to chaos. humans dont just have lust or greed or whatever. we have a little bit of everything. i think warhammer universe as, the cause justifies the means. so for example a player burning an npc in the name of the emperor because he was a heretic is fine but doing the same in order to hide his unfaithfulness is not. award cp according to that. hiding in the darkness or coming out to the light of the emperor is only a choice  . awarding malignacies that fit the circumstance is always nice!  

Have you checked Gifts of the Gods on page 290? The vast majority of them have mechanical effects, too, in addition to narrative ones (though one might argue the latter would be more important).

I guess you are talking about this article from TheWorldSmith (forget about the forum search engine, use an internet search engine instead).

I had started something much, much smaller a long time.
 =======================================================================
With kind regards: Gregorius21778
My blog
P.S: Hey, Asmodee! We want our signatures back!
 

Well the issue here is that you're oversimplifying corruption and as most do oversimplifying what Slaanesh is about.
Your medic talking about sex and suggesting they flay someone's hand for the prints is nothing.
Slaanesh cares about the pursuit of an experience, not the act unless it leads to it.
Your medic flaying their own hand to see what it feels like is something Slaanesh would care about.
Sex is generally the gateway to most Slaaneshi cults, but is not necessarily something Slaanesh really cares for anymore it's way too basic for them.
Corruption by allegiance is brought about by specific mutations based on the God in question. Examples exist in Black Crusade as marks or gifts of the gods, but it's not something for Dark Heresy as the power levels are different.

No, not really. We have different ideas on prep. I think you're demanding too much of yourself and not letting the book work for you.
 
You've no need to make a planet, Askellon has quite a few you could use. No need to craft encounters when the world defines what there is on the planet and you can gauge the number of them with the encounter system.
 
All the other stuff is just things I tend to come up with on the fly.
 
Tell the players, "You need to infiltrate this prison. How do you want to do that?" Let them give you an idea of what they will do. Go from there in terms of GMing.
 
It's ok, you're fine being confused. Don't let it overwhelm you, and let the game system work for you.
 
Some things you should know before the game:
 
The prison - Where is it, a measure of it's forces, the general layout, some notable npcs, where the assassin is, how they are being guarded, what will the assassin do if they are released.
 
The acolytes - Where are they starting? Are they on the planet the prison is on? Or are they to be sent there on a ship once they are caught? Whatever planet they are on have an idea (very rough little seeds of an idea) of what trouble they could cause if they bite and say "We want to do some crime and get sent to the prison."
 
That's about it, note the page numbers of the enemy stats you think you might need and don't worry too much.

Because of scheduling issues my group tends to meet about twice a month whenever we can work out a common day/night, and we run LONG! By long I mean start before sundown and stop well after sunrise often.
Everyone has their own little quirks and moments that bring them gamer-bliss, so I try to include little bits and pieces of things I think they will appreciate, enjoy and otherwise make the game memorable and special for them.  Characters personalities and motivations are heavily tapped to make things something more than just some random mission.   This stuff is PERSONAL!
I mix in a healthy dose of mystery, intrigue, epic scale backdrops with micro-scale stories in the foreground, hands on investigation, moments for special skills, training and unusual backgrounds to shine. My villains tend to be deeply offensive to at least one of the party's sensibilities.  Not necessarily my PLAYERS' sensibilities, but at least one of the characters should be OUTRAGED and trembling to deal out the Emperor's Justice on the offending baddie.  Mix things up.  If the last three "big bads" have been awful killing machines with demon weapons and vulnerable only to a holy melta-gun during the full moon, then perhaps the next villain should be some insane scribe who wishes to offer up knowledge to the Emperor by burning every book in a vast library that (just happens) to be the secret library of an Inquisitor! Holy fire purifies all, purifies the humble text for He who dwells high upon Terra that he might learn every letter!  My acolytes serve an Ordo Hereticus Inquisitor, but sometimes investigations into some reported heretical cult are in fact a stealthy xenos plot to do "bad xenos stuff".  Worse, perhaps the fairly harmless looking simpletons are actually in need of a good Maleus investigation?  The idea is to keep them guessing, while not suspending disbelief. Your plot twists should make sense, maybe not at first, but once they uncover enough clues the little murmurs of "holy crap, are they connected to those weird heretic monks from 3 cases ago?" will bring little happy GM moments.  That look of dawning awareness as one or more of them figure out what they have stepped in this time around.
Personolize it. Make it mean something for the characters.  Obviously the evil plots and schemes do not all revolve around them.  Far from it! They are holy instruments of the Emperor's divine wrath, though troubled and human. Total abject bad-buttock skull crackers on a mission and serving humanity in secret, at great personal expense. They are but tiny cogs in an impossibly vast organization that spans the galaxy, but the workings of the smallest cog is vital to the smooth running of some giant metaphysical clock.  They are meaningless dust, yet they are vital!
I like to mix in some comedy and light elements to offset the terrible gothic horror in sometimes absurd ways, often with memorable NPCs, bizarre scenes or just amusing contrasts. Vividly describing both tragic and glorious moments for individual characters also really helps set the mood. Also, steal shamelessly from anime. Trust me, this works great as long as you are careful to select suitable shows.  Dry, dark humour really sets the mood for DH, so be shameless about it if it improves the entertainment value of the game in thematically appropriate ways. Yes, stupid, criminally ignorant gits in tattered rags spouting off junk science to the Adept and Techpriest to show how educated they are in the miraculous ways of maple syrup is just **** funny! "It's a miracle substance, it is! Cures bunions and warts! Makes paper stick together! Let's see ordinary spittle tackle that job, mate!  Not up to tha' task, that's whatfore..."  It is even funnier if the ignorant bastard actually has a useful skill burried in all that rubbish.
Our Techpriest is played by someone who was a 40K virgin when characer creation started and is now totally immersed in the Cult Mechanicus. His laptop now proudly displays the Omnisian Skull-Cog emblem and you would mistake him for a long-time Mechanicus otaku.  The big meat-mountain guardsman on the team is wrestling with exactly which types of heretics and xenos he hates MORE! Oh, he hates them all, and it started with orks, but his list is growing!  The far from athletic Schola-trained adept cheerfully wades into combat alongside the heavy hitters, smiting His foes in humble yet effective ways and is developing into an interesting person. Our noble cleric is a bit of a party-girl and was sent to the Tarsan chantries to shape up...  Instead she ended up working with the Inquisition using her natural charisma and ability to drink like a Kennedy to uncover secrets. The Scintillan assassin is a Hong Kong action cinema anti-hero, doing horrible things to bad people with many, many empty brass shell casings trailing in his wake as he dreams about the interesting women on his team that are all above his social status. Then we have the noble Cadian guardsman who is their Inquisitor's designated Primus, professionally and stylishly dispatching the Emperor's many foes with lasgun and sword, giving focus to the team and shouldering the sometimes unpleasant burdens of Inquisitorial decrees so her team can focus more on what they love: Doing awful things to awful things!

Hey, thanks for the answer.
We played yesterday and the thing is that the final fight went just as you said - our tech-priest managed to pile a melta and four excavation chargers together. He even managed to roll 07 when he tried to plant the bomb device on the back of the Spyder. They sweated and dodged his attacks for about 5-6 turns until one big boom happened. It almost killed our Arbiter with shrapnel.
But otherwise party seemed satisfied on the plot and I was tired. The next session they will start at the old dude's mansion. Couple of fights and quests for another 6-9 hours and we're done with the first mission.

Not sure how helpful this will be considering you mentioned your session was going to be fairly soon but one option for a relatively low level Necron BBEG is a single Necron wraith. There is a wraith in Tome of Fate for BC that you can use but remove the force field and probably halve its weapon damage to make the fight even close to fair. Mind you, your players could get their hands on decent weaponry which could turn the tide in their favour.
 
If you ended up sticking with the canoptek spyder, I'd consider it an achievable fight if the party had more than just the single melta bomb and krak grenades that you mentioned. Toss in a mining laser (lascutter), some det charges, and maybe allow for krak grenades to be thrown as a bundle (house rule of mine but similar to how det charges work: +2 damage and penetration and increase the Blast quality by 1 per extra grenade). One other thing you could do is remove the spyder unnatural toughness of +6 and add that onto the armour. That means that any high AP weapons will become that much more useful.
 
Let us know how things went. It's going to be a rough fight regardless because mere humans are not meant to fight Necrons ever.