The Vok are apparantly supernatural beings from the Shattered Beasts universe.
"We live to destroy."
-The Vok explaining their purpose
The Vok were once the Swarm, a non-sentient mass that healed and restored life to everything it touched. But this was ruined when Optimus Prime, the most famous Autobot Emporer of Destruction, exposed it to the light of the Corruption Matrix turning the innocent being into the twisted Vok.
These creatures now live only to destroy and kill, maim and rend. Because of this they where sealed away by a quadrent lock, imprisioning them in Nexus Zero (SB). Now they can only influence Transformers through their sparks manageing to corrupt some but most of the time failing. But now the quadrent lock has been tampered with, a transwarp disturbance has cracked it, and they emerge to see a primitive planet ripe for destruction.