Undead - R

Ravens = Ravens are animals commonly associated with Death. Some Resurrectionists find that the animals are drawn to them and may even be kept as pets. 
Reapers = Spirit servants of Death itself, Reapers are more often than not the allies of Resurrectionists.
Resurrection = Resurrectionists can transform themselves into various types of Revenants, be they True Immortal or Undead. 
Resurrectoin Techniques = Resurrectionists will frequently use special methods to increase their ability to raise the dead and command the forces of Death. 
Revenants = Anything that has died and been brought back from the dead is technically a Revenant. And if it's a Revenant, it probably falls under the influence of the powers of the Resurrectionists.