Angst:
 
Angst is the permanent power of the Shadow. The more Angst a Shadow has, the more powers it can offer a Wraith in Shadowstate, and the more dice it can offer a Wraith to "help" on a roll, via the Heart's Thorn.

Also, the amount of Angst forms an upper cap on how high a Wraith's Morality can go. Should a Wraith's Angst ever reach 10, the Wraith becomes one of the Damned, and is no longer a playable character.

Collecting Angst
 
Angst can usually only be gained by a Shadow's succeeding in a Harrowing, as detailed in "Harowings," under Dirty Tricks.

Using Angst
 
A Shadow's level of Angst is an indication of:
 
* How many Thorns a Shadow may have active at once under normal circumstances. A Shadow with two or fewer dots of Angst may have one Thorn active, a Shadow with three may have two Thorns active, a Shadow with four may have three, and so on.
 
 * How many Thorns a Shadow may have active during Shadowstate. When the Shadow and Wraith have agreed to pool their efforts, one Thorn may be offered per dot of Angst.
 
 * How many Dice the Shadow can offer while using the Heart's Thorn. Each dot of Angst allows for one Die to be offered, up to a limit of nine per roll.

* How many Tainted Essence the Shadow can spend to negatively modify the Wraith's Ossification roll.
 
* If the physical symptoms of Thorns are present or not. Once a Wraith reaches four Angst, a Thorn's symptom - most often the Heart's Thorn - manifests. At five Angst, two Thorns' symptoms appear, three symptoms appear at six Angst, and so on. If the Wraith has any Eidolon, each dot is subtracted from the Shadow's Angst when making this determination, delaying the inevitable manifestation of the Wraith's growing inner darkness.

Tainted Essence:
 
If Essence is the free-floating power Wraiths gather from their Anchors, or what they can skim or siphon from the Living, and other Wraiths, then Tainted Essence is its darker opposite. This is the power the Shadow collects for Itself, as the Wraith goes about her business. And it is the bane of every Wraith who values both her sanity and her continued existence.
 
Shadows cannot have as much Tainted Essence as Wraiths have Essence: their potential pool starts out at ten, and can go no higher or lower. Any time a Shadow would stand to gain so much Tainted Essence that they would go above ten, the extra energy bleeds off uselessly, taking the form of wisps of dark energy that can only be seen by those sensitive to such things.

If a Shadow's Tainted Essence ever goes past a Wraith's Morality, the Shadow has a chance to trade it all in for a dot of Angst, via a Harrowing. This has the effect of lowering the Wraith's moral ceiling, possibly even knocking away a dot of Morality. And this, in turn makes it that much easier for a Shadow to get another dot of Angst, and so on.

Collecting Tainted Essence
 
Shadows cannot collect Tainted Essence the same way that Wraiths collect regular Essence. Instead, they have to gain it by tricking their Wraiths into giving it to them, one dot at a time. It's slow going, but there is a point where the Shadow can have the Wraith eating out of Its hand, and once that point is reached it's often straight downhill from there.
 
To gain Tainted Essence, Shadows must:
 
* Agree to enter Shadowstate with the Wraith, offering the Shared power of its Thorns to be used at the Wraith's behest. When a Thorn's power is thusly used in Shadowstate, one Tainted Essence is gained, regardless as to whether the roll to activate it is a success or not. In addition, if that roll is an Exceptional Success, then one Tainted Essence is gained for each success past the first. And if the Shadowstate should be extended, the Shadow gains an additional dot of Tainted Essence for each Scene past the first.
 
* Use the Heart's Thorn on the Wraith's behalf, outside of Shadowstate. This Thorn allows the Shadow to offer extra dice to a Wraith for certain rolls, and any time one of those dice comes up '10' on a roll, a dot of Tainted Essence is gained. {Note that the Shared power of the Heart's Thorn acts like a normal Thorn - a dot of Tainted Essence is gained every time it's used}
 
* Get the Wraith to feel the Virtue or Vice that goes with that Shadow's Type to the point that the Wraith either feels it extremely, or acts on it without hesitation. Should that happen, the Shadow can roll one die for every dot of Angst it has, and each success gives a point of Tainted Essence.

Spending Tainted Essence
 
Tainted Essence can be spent to do things as well, though a few of these expenditures give the Shadow a chance to win it back.
 
Shadows can spend Tainted Essence to:
 
 * Fuel the Shadow's powers, which are known as Thorns. Most Thorns require one point of Tainted Essence to activate, but some require more than one, and others require that extra points be spent to keep the effect going.
 
* Fuel the Wraith's Numina, or heal damage, as though it were regular Essence, should the Wraith ask for help. In this case, the Tainted Essence is spent, but the Shadow can try to win it back with interest by rolling one die per Tainted Essence given over. One success gives the Shadow back all the Tainted Essence it let the Wraith borrow, and each success past the first gives an additional point.  

* Negatively affect the Wraith's Ossification roll. Each dot of Tainted Essence spent takes away one die.

* Attempt Catharsis or Dissolution, as detailed repsectively under Dirty Tricks.
 
* Try to gain a new dot of Angst, as detailed in "Harrowings," under Dirty Tricks.