Origin of Vampirism

{t}, Add {b} to your mana pool.
Whenever one or more Vampires you control
attack, create a Blood token. (It's an artifact with
"{1},{t}, Discard a card, Sacrifice this artifact:
Draw a card."
{b}{b},{t}, Pay {x} life: Choose any creature with {x} converted mana cost from any graveyard
and return it to the battlefield under your control.
It is a vampire in addition to other types.