Nioh and Nioh 2 (including all DLCs) are also bundled in the Nioh Collection on PS5.
The Sub Mission The Rising Shadows takes William to an undercover Mission to hunt down the assassins who have hidden at the depths of the Edo Castle cellar.
Sub Mission – The Rising Shadows Walkthrough
Advance forward to find the Shrine at the edge. When ready, go past the Shrine to follow a dimly lit narrow trail. Continue straight ahead and ignore the Onmyo magician. Past him is a flight of steps to descend, as you reach the lower level, stick to the right side to come across a set of steps, ascend them then drop off to find some Ninjas.
Take them out, then continue along the tapering path, turn right and be wary of the Archer that fires Flaming Arrows, take cover if need be and snipe him from afar. Eliminate the Kusarigama Ninja that is patrolling here to clear the path. Proceed to door that was previously guarded to enter a dark room with a lone candle. Go through the dark doorway, then head straight, go around the railing then drop off down the ladder.
Stick along the right path, through the narrow ledge, drop down to the red puddle, then enter through the charcoal dyed double doors. Be careful of the surrounding mini Umi-bozu and Yokai that inhabit the underground.
Descend down the path, passing through an arch lit with mini torches, then make a right turn. Now turn to the left, ascend the steps to exit the water contaminated area. Turn right then left and approach the Yokai Realm to trigger the Yoki. Finish it off, then enter the area it was blocking. Make a left, passing by a narrow area to exit through a doorway lined with some cobwebs. Descend the steps then examine the corpse near the lit torch for an item.
Take out the Yoki that is idling at the center of the path. Then proceed to the path by the torch, descend the steps then go through the red puddle. Ascend the steps on your left by the torch, make a left then race to the other side, being careful of the Dual wielding Ninja that ambushes you at the back as you go. Check the corpse on the right side for an item. Ignore the door at the end, and return to the other side (the right path that you neglected earlier). Before you enter the hall, snipe the idle Onmyo magician, this will alert the nearby Ninja. Take him out next, then locate his dead body to complete the Mission.