Vitae is the life energy that witchs manipulate to fuel their magic. It is drawn from various sources, depending on the type of Thaumaturgy being practiced. Each school of Thaumaturgy has a cantrip which can be used to gain Vitae.
You have zero Vitae by default, and must gain it through your powers. You can spend Vitae to fuel more powerful effects, or to enhance your spells.
Your maximum Vitae is equal to your witch rank + your spellcasting ability modifier.
Spells
Antimagic
Vitae: you can use Absorb Magic to absorb 1 Vitae from a spell, which may dispel it.
Lock eyes with target and learn their secrets--but they learn yours, too
2
Magic Jar
You detach your soul from your body, which becomes helpless. You can possess creatures and objects, perceiving from their point of view, and attempt to control them from within. At higher rank, you can force the soul out of a target without leaving your body.
3
Demi
You create an evil clone of the subject.
Transmutation
Vitae: you can use Transform Object to destroy a crafted object. It must be something requiring skill to create, and at least one day of work. This grants you 1 Vitae.
At higher ranks, you can use Transform Object to destroy more valuable objects to gain more Vitae.
Change one material into another; turn lead to gold; turn your enemies to liquid
Undeath
Vitae: you can use Control Undead to take control of a mindless undead creature. Once under your control, you can snuff out its animating force to gain 1 Vitae. More powerful undead yield more Vitae.
Scan: When using Sense Magic or Weavesight, you can detect which spells a given creature has available, and how many charges/Mana/etc, as a swift action.
Rapture
Re-Vitae: Whenever you spend Vitae, you heal yourself for medium damage per Vitae expended.
Sympathy
Sympathetic Magic: Whenever you encounter a hostile spell that can distinguish between friend and foe, you can roll a proficient Charisma skill check against the DC to convince the spell you are its friend. The result of this check remains true for the duration of that particular instance of the spell.
Spell Stowaway: Whenever an enemy within range casts a beneficial spell, you may, as a reaction, manifest a copy of their spell affecting you or an ally.
Vital Shield: Whenever you are harmed by a spell, you can expend 1 Vitae to reduce the damage by half, or to gain advantage to the saving throw.
Prognostication: at-will, swift, ranged; you predict the target's next action. When they take it, whatever it is, you may spend a reaction to react to it.
Transference
Manifest Phylactery: at-will, swift, requires a sympathetic component; you manifest a temporary phylactery of the target, lasting until a short rest. You can convert this to a permanent phylactery if you conduct the normal ritual immediately after combat.
Spell Channel: if you inflict harm with a spell, natural attack, or a weapon you're currently wielding, you can use that as a channel to puncture that opponent's defenses. This can be used to target them with a spell regardless of line of sight or effect at will. If expended, it can grant advantage to one spell or attack roll against them, as well as increasing damage by 50%.
Verity
Mystic Eyes: at will, you can see through glamours, figments, and invisibility spells.
Entropy
Bad Luck: Shit happens. It's a well-known axiom of witchcraft. But with careful study and perception, you can learn not to be in front of the fan when it happens. When you roll a d20, and the result is at or below your Entropy rank, you can "store" the result, rolling again. When you have a stored result, you can impose it upon any other PC or NPC whenever they roll a d20, expending it and forcing them to take your result.
Death and Decay: All things decay. This is something you've accepted. But you don't have to dive into the grave on purpose. You gain Resist 50% (necrotic), and advantage to saves against death magic and ability damage/drain.
Death Becomes You: The undead are the antithesis of the living, and naturally hate, fear, and long to feed upon them. You understand that, and sympathize with them, and, to an extent, they respect that. Mindless undead become indifferent to you unless actively commanded to attack. Your own undead servants gain inspiration once per encounter.
When you are missing Hit Points, you can add your HP debt to the damage of any attack or spell you inflict, to a maximum of 100% of the attack's original damage. This does not change your current HP.
When you drop to 0 HP, you have the option to immediately begin concentrating on an effect which prevents you from dying. While active, you do not need to roll death saves, and you can act normally. Any damage you suffer should be tracked, because if you stop concentrating while you are in negative HP, you will begin to die as normal. If you heal above 0 HP, the effect ends.
You can walk on water by freezing it beneath your feet. You can also move across ice and snow without penalty. You may imbue this ability to your mount, or to allies within 5 squares while concentrating.
You gain a reaction to an incoming projectile attack against you or an ally within range. At the cost of 1 Vitae, you can transmute the projectile into a harmless substance (bubbles, dust, etc) just before it hits you.
You can use Objectify on yourself as a swift action, turning your flesh into an amorphous, gelatin-like substance that looks and functions the same, but you gain Resist 90% to slashing and piercing damage.
You can create special Soul Gems to house the soul shards of Drain Soul. If a creature dies while you possess their soul shard in such a gem, you trap their soul in the gem.
