Kataribesou ~Ensouki~ (かたりべ荘～淵藪記～)/guide/Other bosses

Nanji (Genma Shogun)
This is an optional secret boss, she will randomly appear in the Tunnel between Cyber World (after Zafra's place) and Ancient World (Spirit Treasure's room) after the third lap and when Shura/Shura's Incarnation is activated. The exact way to trigger the battle is unknown, but it seems to be random.