Editing Warhammer 40,000/9th Edition Tactics/Space Marines (section)

====Psychic Discipline: Umbramancy====
Most of these are so bad they're not worth talking about, so take this discipline if and only if you have use for an Enveloping Darkness/Shadowstep Librarian, which combine to being best on a Librarian with poor mobility trying to help support Vanguard Veterans or the like.

#'''Umbral Form''' ''(Blessing, Warp Charge 5)'' - The psyker gains a 4++.
#*This is bad, there's no sugar-coating it.  
#'''Enveloping Darkness''' ''(Malediction, Warp Charge 7)'' - One visible enemy unit within 18" cannot fire Overwatch and subtracts one from their hit rolls. Basically a psychic Shock Grenade.
#'''Spectral Blade''' ''(Blessing, Warp Charge 5)'' - Until the start of the next psychic phase, the psyker's Strength is equal to their Leadership. In addition, they have AP-4 when resolving an attack against a unit with a lower Leadership. In most cases, this will make your Librarian Strength 9, and you can guarantee the AP bonus by using one of the numerous Leadership penalty sources available (suddenly, Fear Made Manifest gets better as a warlord trait).
#*''Never'' put this on a Force Axe wielder - S11 is a waste of your time.  You'll murder harder with a Primaris Librarian with Force Sword than anything else, but as this benefits less from the AP buff than a normal Librarian with Force Staff does, the latter is more likely to find situations where it's worth casting this over Smite, which is still very rare - in either case, you need everything to line up perfectly: the target has to be of a T where you double your output (so T6-9 for a Force Sword, T8-11 for a Force Staff) ''and'' you need to qualify for the AP improvement ''and'' the full AP-4 has to apply, so Sv2+/6++ or 7++ only.  Skip this power if possible.
#'''Shadowstep''' ''(Blessing, Warp Charge 7)'' - One {{W40kKeyword|Raven Guard Character}} within 18" of your Librarian redeploys wherever he wishes while 9" away from the enemy. Once again, it can be used to send a Chaplain to support infiltrated Marines, or to teleport around a Terminator or Gravis Smash Captain. Did anybody say, Chaplain Dreadnought?
#*Works on bikes (and vehicles) just fine, and of course works on the Librarian if you want to line up a second power, like Smite.
#'''The Abyss''' ''(Witchfire, Warp Charge 6)'' - Select one visible enemy unit within 18". Roll 3d6; for each each roll of 4+, the target takes a mortal wound. If any models are destroyed, then the unit suffers a -1 penalty to their leadership for the rest of the turn.
#*Deals 39/36 (1.08) MW on average; if you're targeting a W1 unit (so even 1 MW gets you the penalty), the odds of killing at least one dude for the penalty is net 63.19%.  
#'''The Darkness Within''' ''(Witchfire, Warp Charge 6)'' - Select up to 3 enemy units within 18"; roll 1d6 for each unit. On a 4+, they take a mortal wound. If you rolled a 10 or higher on the psychic test, add 1 to the d6 rolls.
#*Worse than Smite, of course.  Deals 0.39 mortal wounds per unit (so any given unit probably won't suffer a single wound); against 3 units you'll manage 7/6 (1.17) MW on average, but that doesn't mean the usually single mortal that gets through will be on the unit you really want it to be on.  Worthless - not even as good as The Abyss, which deals fewer Mortals on average but lets you pick where they go when they do happen.