Basic Abilities

Vitae

All thaumaturgical spells require a power source called Vitae.

Various ways to get it:

• Let Blood: use a bit of your blood (or someone else's) to power the spell at the cost of some HP.
• Drain Life: drain someone's life force to gain Vitae.
• Absorb some from the surrounding environment (favorite of winter witches)

Don't assume every spell costs 1 Vitae or somesuch. Many spells contain their own method for powering them. Some allow empowerment of the spell's effect by adding bonus Vitae.

Chroma

All moral choices have consequences in the cosmic scheme; this is known. When magic is involved, the consequences usually come quite a bit faster.

Any questionably moral act committed with magic can cause a stain upon the practitioner, metaphorically "darkening" their fate until such time as the cosmos decides to even the score through application of what might seem to be ill fortune. Conversely, those who do selfless, altruistic acts can "brighten" their fate, which may result in good fortune coming there way. Naturally, the two opposing "colors" cancel eachother out.

This concept is referred to as "Chroma" for several reasons:

• It has the connotation of "color", i.e. "the color of magic" or the metaphorical colors of good and evil upon the soul
• It sounds like "karma". But it's not Karma. That's a completely different concept in real Earth religions that is extremely misrepresented and misunderstood in western society. It would be an insult to use the term so incorrectly here. But Chroma is a lot like what westerners think Karma is.

Thaumaturgists understand that the cosmos holds certain morals to be absolute. Harm is harm, help is help. Context matters, but not enough to justify outright harm. Neither a god, nor a church, nor a holy book is necessary to elucidate the rules or judge the particulars--the Universe enforces its own morality, with no exceptions or loopholes. Of course, intelligent practitioners, understanding just how it does this, can find some clever workarounds.

Many practitioners find a way to accumulate good Chroma through public service. This gives them a certain insulation against the occasional dark Chroma they might need to accrue to survive a violent encounter. But the cleverest black witches wield Chroma itself as a weapon. You see, when the Universe decides to strike, like lightning seeks the nearest conductor, Bad Luck seeks the darkest soul. Black Witches have a sense of when their Chroma is coming due (and some ability to manipulate that), and plan to find themselves in the vicinity of even worse souls when the time comes. Also, it's generally considered good sense among black witches to do everything possible to shift Chroma onto other people. Why kill your enemies when you can tempt someone else into an equal exchange that happens to grant them the power to take care of said enemies independently? That sort of thing.

In other words, the mechanics of Thaumaturgy incentivize witches to act like witches.