According to legend, the Quietus Discipline was developed by the ancient founder of Clan Assamite, who are still its only common practitioners, and was intended to allow them to have control over the blood of other vampires, the better to pass judgment upon them if necessary. Quietus affects and transforms the essence of the blood within a body, allowing its users to draw supernatural properties from it or allow it to become dormant at will.
Basic Powers
Silence of Death: Like the silent movement of blood in your veins, you can extend your powers outward to create a zone of complete silence around you, in which no sound can be made or escape. The silent zone extends for about 10 feet around you, and while no one hears any sounds that should have been made within it, you can still hear noises that would have been created outside that range.
Scorpion's Touch: You can transform your blood into an acidic poison, injuring and sickening those who are touched by it or ingest it. Anyone who drinks your blood while it is thus poisoned becomes severely ill, and anyone you poor or spit that blood on is burned as if by acid. Vampires can recover from these effects by healing themselves with blood, but mortals generally become deathly ill or simply die within a few minutes.
Intermediate Powers
Dagon's Call: By touching a victim, you can cause some of your blood to pass through your skin and into their body, there to wait for you to cause it to burst violently back out of them whenever you wish. Once you have done so, the blood erupts out of their organs, tissues, and orifices as it responds to your call for it to return, usually causing spectacular pain and injuries in the process. This power does not create a Blood Bond, since it does not actually involve a victim imbibing your blood.
Baal's Caress: You may cause a small portion of your blood to become so frighteningly toxic that it inflicts damage on others as if it were literal flame. You may only do this with a small portion of your blood at a time, and it can only inflict its terrible burning pain on them if you manage to introduce it into their bloodstream in some way.
Advanced Powers
Blood Essence: An intensely banned power (but nevertheless one still in existence), this skill allows you to extract all the hearts-blood of a vampire into a thick potion, killing them in the process. The resulting potion literally contains the dead vampire's soul, and can be consumed at any time in order to have the effects of a diablerie. It can also be introduced into a dying or exsanguinated human being's system to make them into a ghoul, although most vampires would consider this a distressing waste.
Taste of Death: You can spit some of your blood at someone, and make it so terrifyingly acidic that it burns even bone to unusable sludge. It can also destroy most inanimate objects, so for obvious reasons it cannot be placed on a weapon or projectile, only directly coughed onto your target.
Elder Powers
The elders of the Assamite clan seldom leave their traditional territories and even less often give up their secrets, which is probably a safeguard that benefits the entire rest of vampiric society. Elder powers of Quietus include sucking blood directly out of their victims via touch, preventing a vampire from being able to use blood to heal wounds, forcing or denying other vampires the ability to spend blood, or even temporarily weakening someone's blood so that they effectively go up a generation.
Important Things to Keep in Mind
Quietus has a bad rap with most vampires, who consider it a nasty powerset geared toward assassination, so you may face some discrimination if you use it frequently or publicly. Poisons created from your blood are potent toward everyone, including yourself, so once you've created one, be mindful that it will hurt anyone and anything it comes into contact with.