Blood of Zul'jin

Blood of Zul'jin drops from Zul'jin in Zul'Aman. It starts, which rewards (and a bit of personal amusement). There is only one drop per kill.

Rare to Epic
When Zul'Aman opened, the Blood of Zul'jin was a drop; in Patch 2.3.2, it became an  drop, much like the other "parts of bosses" (Kael'thas' Verdant Sphere, Magtheridon's Head, etc.)