WUCHANG: Fallen Feathers

Finding the Boss and Shortcut

When you make it to the Shu Sanctum, head out the main entrance towards where the tough samarai enemy was/is. Either climb the ladder to the rooftops or cross the invisible bridge, but explore up that wooden buildings area.
You'll come to a fire mini boss who you should fight to obtain a useful fire spell for this boss. Continue up to higher ground and there will be a bloody stair path up to the boss arena but before entering, take the path to the right to knock a tree down which opens a shortcut back into Shu Sanctum.

Fighting the Boss

Phase 1

She's fairly basic when you see it. She mostly slashes her hands, dashes/jumps around, and spits streams of...blood?
You can stick behind her or to her side fairly well in the fight for much to miss you.

When she looks like she wants to hug there will be an audio queue warning of her grab attack. It can be bull sometimes instantly activating with practically no warning.
But she can also dash at you as a normal attack so listen for the audio to differentiate the attacks.

When she sprays blood horizontally across the arena, intentionally dash through it for an easy free charge and get free hits in.
When she spits blood vertically, expect a followup of two pecks into the ground and a swipe to avoid.

Phase 2

At about 50% health she stands up and screams. You need to back away or you will be stunned and need to mash B to escape. The scream will transition into a long blood spray around the arena. Get close to her and it will mostly go over you while you get free hits. Be warned she comes down hard after which damages you so just dodge on that. She then needs to recover for more free hits.
You should get a bunch of damage in then and little will be different then to finish her off

Tips

The boss is weak to fire so use the Infernal Flames spell you collected but only in close range as she can move around too much to end up missing. You also should have been taught how to temper your weapon with fire, but you need to use the temperance inventory item for it to activate.

My preferred weapon is the spear, but if you prefer the axe or another weapon, don't try to switch weapons because you're dying a lot. Persist, you can do it.

Before entering the Arena, set your weapon on fire. This will help increase damage.

Be quick and attack the boss's back whenever possible. Running + helps a lot in this battle (with the spear, in this case). If you find a better move with your weapon, share your comment.

Something I didn't do, but when I did it worked: Attack the boss before and after he gets up and screams. I simply stayed away, which killed me in this battle. Be aggressive. Attack the monster before it enters the second phase. You'll probably stun the boss and deal a lot of damage to speed up the process.