Ninja Gaiden II/Chapter 14: Poisoned Blood

"To save Sonia, Ryu fought his way through a sea of blood filled with vengeful spirits, reanimated by the evil of the Underworld. Now he confronts the Queen of the Greater Fiends in a final battle to the death. Dagra Dai's evil incantations are complete; the resurrection of the Archfiend is at hand. The Dragon Ninja walks the blade separating life and death."

Part 1: Blood Caverns
Collect the glowing object here to obtain the Heart of Azure Lightning. Proceed up the path to the iris door and open it. Within, you will be attacked by several Cyborg Fiends. Kill them off and search the corpse here for a Devil Way Mushroom. Progress to the next room for a Muramasa Statue. Clean him out, you have a lot of difficult battles ahead.

In the next room, several Centaur Fiends will attack. Kill them off and search the two corpses here for some arrows and a Devil Way Mushroom. Enter the next room and use the Dragon Statue here. Proceed into the next open area. In the pool ahead, several Red Worms are swimming. Drop into the water and drill them with your Gatling Spear Gun. When they are finished off, water run to the gate on the opposite side. On the left is a chest containing Red Ki Essences. On the right is a corpse holding an Herb of Spiritual Life. Open the gate for a cutscene.

Boss: Fiend Genshin
Genshin. Again. He has the same set of attacks as he always has, but is a little bit tougher now. Kill him off and you get his sword, the Blade of the Archfiend. Watch the cutscene for another boss battle.

Boss: Greater Fiend Elizébet Redux
Elizébet is the same as she was the last time you fought her. She will repeatedly use her Flying Swallow-like move. Dash around and use your Flying Swallow attack back at her and use Y combos to take her down. When she falls, collect the Heart of Crimson Blood from where she fell.

Part 2: Dark Plane
Enter the glowing portal ahead. Once through the portal, you will be in a black room. Open the chest behind you for an Herb of Spiritual Life. Use the Muramasa statue here to stock up on items and then use the Dragon Statue. Continue ahead through the large door at the far end of the room.

After the cutscene, proceed up the corridor killing swarms of Purple Fiends and Golden Bat Fiends. A cutscene will interrupt you. Proceed again, to the iris door at the end of the cavern. This will begin a boss fight.

Boss: Infernal Priest Dagra Dai
This guy looks tougher than he actually is. Immediately after the battle begins, he will spawn a group of Purple Fiends. Take them out with ninpo and dodge his air attacks until he lands on the ground. When he lands, take out the Blade of the Archfiend and go to town on him with Y combos. Avoid his lightning and dash toward him when he teleports. Repeat this dance one more time to take him out. When he dies, watch the cutscene and then swim across the water to the platform. The chest here has an Herb of Spiritual Life in it. Climb the tentacles here for a cutscene.

Boss: Archfiend
He's an ugly customer. Examine the corpse in this area for arrows if you need them. The bow is the only way to damage this boss. Hit him in the head with a charged arrow shot to do damage. When you do this, the sphere in the center of his body will glow. Land an arrow shot here to damage him considerably. Avoid the blood that falls when you damage him, it hurts you badly. Also avoid his laser breath and ghost attacks by dashing. When he flees, follow him. There are shafts for you to perform Flying Bird Techniques in. Repeat this until he falls. Also of note: If you kill his ghosts with ninpo, they will drop Yellow and Blue Essences.This is good news if you run out of healing items during this fight.

Boss: Archfiend, Second Form
That's some potent blood. This boss can be very difficult if not for this simple hint. Head left of his claw when he is clutching the cliff. If you get between his claws he will grab you and probably kill you instantly. Stay on his left claw. Use the Blade of the Archfiend and lay down a few Y combos until he shows that he will be doing another attack. When he does, dash twice to the left. Repeat this until he detaches from the cliff. When he flies straight backward, simply dodge the meteors. When he flies left, dodge his dash attack by hugging the rear wall. Occasionally he will slam into the wall and go walking around for a while. Avoid his tail here and slash his legs with the Blade of the Archfiend's Y combos. Lather, rinse, repeat. Watch the end cutscene. Congratulations!