In my work to write up Custom Chapters I have made some inroads into making custom Psychic Powers for one called the Devours. And I'm looking for some input if these seems like they are reasonably balanced and potentially useful, or at least interesting or cool.
Description: Deep within every Devourer lies a dark urge to consume the flesh of their fellow man. The Librarian can harness this cannibalistic instinct and channel into the minds of their enemies, causing them to fall to an overwhelming urge to consume their erstwhile comrades. The target must attack the nearest target and start to consume its flesh. If left undisturbed the target will strike until it has slain its target and then spend 1d3 rounds to consume the flesh of the dead before seeking a new meal. In the case of a Horde the Horde will attack itself with its melee weapons and if suffered losses to magnitude the Horde will stop for 1d3 rounds to consume the dead before it makes a new attack upon itself and so repeat the formula.
Form of Horror
Description: Within the Devourer gene-seed the legacy of Sanguinus has taken a dark form of murder and mutilation. Many brothers of the Chapter have permanently fallen to horrible forms of mutation but the Librarian can harness into this otherwise forbidden form and force his body to adjust to it for a temporary period of time. When activating this form the Librarian’s mouth is widened and filled with great fangs to tear flesh and his hands grow into fearsome talons to rend apart even armor. The Battle-Brother gains Improved Natural Weapons, Natural Armor (2) and +10 in S, T and Ag but must make a Willpower Test whenever slaying a target to resist the urge to spend 1d3 turns to devour the remains of the fallen foe, unless the character comes under attack that is. The Librarian also gets 1d10 Insanity Points and anyone witnessing the transformation gains 1d5 Insanity Points.
Use of this power is more than likely to also create in-game reactions from the Librarian’s surroundings.