Operation Queenslayer was a battle for the survival of humanity fought by Revenants, many of whom were created for the campaign led by Gregorio Silva to eliminate the Queen.
However, due to the immense shortage of Blood Beads in the face of the sheer number of Revenants created during the operation, a great number of Revenants ended up succumbing to frenzy and joining the ranks of the Lost, many being imprisoned by sealing stakes.