Blood golems (also know as anima golems) are mechanical creations of the mogu. They are animated by Anima, a mysterious substance used in mogu flesh-shaping rituals. Blood Golems served the Dark Animus, after it's defeat, the blood elves acquired the powers of Dark Animus and began empowering blood golems on their own.
In Mists of Pandaria EditThis section concerns content exclusive to Mists of Pandaria.
During the battle on the Isle of Thunder, Lor'themar Theron's agents defeated the Dark Animus and secured the power within the crystal. With Animus' powers, the blood elves were able to empower the golems on their own. Blood golems were a perfect advantage for blood elven troops against Garrosh Hellscream.