• Cantrips: All cantrips on the Sor/Wiz list, or from all arcane lists?
  • The spell list in general: Is in dire need of alphabetization.
  • Bloodletting: Metamagic, GP and XP cost mitigation: DANGER DANGER. This is a very powerful feature. I haven't looked over the spell list to see what will happen just out-of-the-box (nevermind what happens when you do something like PrC into Rainbow Servant), but really, as flavorful as the mechanic may be, I'd call implementing any feature like this a fundamentally bad idea.
    Two peculiarities I noticed:
    • Ability damage that can't be naturally healed is called Ability Burn.
    • What happens if, say, you're immune to Constitution damage? There is nothing in the rules preventing undead creatures from becoming Blood Mages, for example.
  • Naming convention: You refer to the class interchangeably as "blood mage" and "blood magus". I don't know the underlying grammar here, but it looks inconsistent.
  • Stigmata: Requires a book/page reference.
  • [b]Blood Pact: Share pain requires a book/page reference.
  • Ritual Blood Bonds: Requires a book/page reference.
  • Scent: Sounds a bit like the lifesense of a wraith. Do you want this to be scent-related? Also, needs a definition of what a "recently deceased creature" is. One minute from death? One hour? One week?
  • Blood Mastery: Are the bonus HP in addition to the bonus HP granted by the constitution increase, or are they a part of it?