While everybody was relaxing after the defeat of akatsuki, Minkai Zokatakei was not. He gets the final fragments of Soul Edge and, for a short period of time, rules the great nations (he does NOT become the Gokage Sennin). Haizo and Seireitou have to find Soul Edge's weakness, and Defeat Soul Edge and kill Minkai Zokatakei.
Final Fragments mini-arc
Still being created