Slaughter Great Emperor had once taken several direct disciples and cultivated them with great effort.
He wanted to pass down his Way of Slaughter.
Unfortunately, in the end, all his disciples failed.
Because the Way of Slaughter involves killing their closest kin, the disciples couldn't bring themselves to do it.
Therefore, even after Slaughter Great Emperor ascended, he couldn't find a true direct disciple.
But to make up for the regret in his heart, Slaughter Great Emperor left behind the Emperor's legacy, the Emperor Head.
He left all his life's learning within the Emperor Head.
Moreover, this Emperor Head wasn't placed within the Purgatory Holy Sect, but instead lost to the outside world.
And he forbade the Purgatory Holy Sect from retrieving it, unless there was someone within the Sect Gate suited to the Way of Slaughter.
This Emperor Head has since become a legend.
