I'd let you do it with a biomantic ritual, where you magically altered yourself to subsist upon blood and use it to make yourself stronger. You could also use diabolism to bind a demon to your body.

This is probably one of my more powerful sponsored magics, I'll admit.

Would pricing it up to [-5] alleviate most of your concerns?

I thought i might be losing my touch, so, this. This one's pretty powerful and ergo might merit a cost of [-5]. Feedback is appreciated. Using this on a character in an IRL game who's basically a combination of Bonesaw, the Vord Queen, Infested Sarah Kerrigan, and a Tzimisce. She is the most frightening and the most adorable character I have ever played.

DEUS VITAE [-4]
Description: You are a master of both mind and body, and have learned to manipulate both raw psychic energy and pure life force, allowing you to do incredible things with biomancy and psychomancy.
Sponsor: Typically self-sponsored, but is occasionally granted by creator gods or gods of fertility and life.
Agenda: Your own, if self sponsored. If granted by a god or other entity, that entity's agenda. Typically, the influence of Deus Vitae will drive you to use your powers in some way linked to your worldview- one user might be constantly tempted to make everyone around her happy, while another, disgusted by his own appearance, might be compelled to twist other's features into grotesque, nightmarish things.
Evocation: You can manipulate blood, flesh, bone, and other vital fluids and systems. You can also manipulate psychic energy, allowing you to use Spirit magic, but with more finesse and skill than a spellcaster without this Power.
Thaumaturgy: You can create and manipulate biological systems and life-forms of nearly any degree of complexity, from an amoeba to an oak tree to a human. You can also manipulate psychic energy and minds, allowing you to use fantastically powerful and precise psychomancy.
Evothaum: You can use any ritual that can be cast with Deus Vitae with Evocation's speed and methods.
Extra Benefits: You may use your complexity and control bonuses from Deus Vitae in place of your power and control bonuses for evocation, so long as the spell incorporates some element of biomancy or psychomancy.

Zion looks great. Beyond the unavoidably nonsensical things like the bottom of his skill pyramid, this seems like a really solid writeup to me. Well done.

I was under the impression that every stress track came with it's own set of consequences, so I'm inclined to say yeah, you can get extra consequences from a high Discipline.

I love it and would use it immediately. It makes ninja-type characters a hell of a lot more viable. Given my whole "incorrigible minmaxer" thing, that probably says a lot about the power. It does seem balanced, though; Imperceptible is probably a [-0] power, the other two are basically stunts.

I'd allow you to do rituals like the super, super SUPER SUPER COOL ONE that Taran just described with Crafting. However, because Crafting isn't a Thematic thaumaturgic specialization, you technically can't, but that's easily solved as saying that your Thematic Thaumaturgic Specialty is Crafting (i.e. scion of a forge god).

were is the rule that allows GM to do it.

Self-Sponsored Magic debt is handled the same way that normal Sponsor Debt is handled. The actual power is below.

SELF-SPONSORED MAGIC [-Varies]
Description: Either you’ve studied a branch of magic long enough to understand and use it intuitively, or you’re a being of such singular power that a unique form of magic emanates from you.
Skills Affected: Conviction, Discipline, Lore, others.
Effects:
Self-Sponsored Magic. This Power is in all ways identical to Sponsored Magic, except that it lacks an external sponsor. The Compels resulting from the debt taken to fuel this power are therefore obviously not connected to any external agenda; instead, they are linked to your Aspects like normal Compels.


As it says, they're linked to your Aspects and are treated like normal Compels. However, as someone (I think it was Haru) said earlier, it might also involve themes of the magic itself- Self-sponsored Wards Magic would Compel you to be cautious and defensive, Shadow Magic would Compel you to be sneaky and deceptive, Fire Magic would compel you to be energetic and chaotic, etcetera.