Prosthetic Arm is a special contraption in Sekiro: Shadows Die Twice that facilitates the use of several tools and weapons for the protagonist, Sekiro.
Prosthetic Arm in Sekiro Shadows Die Twice
- A grappling hook, or more correctly a kunai with a rope attached, is an integral part of the shinobi's prosthetic arm (and most likely the gameplay mechanics as well), and can probably not be unequipped.
- Loaded Axe: A short axe that can overpower and break enemy shields.
- A steel fan seen in the trailer that opens up like a shielding umbrella.
- Shuriken: A shuriken-dispenser, probably the item that looks like a bicycle bell. Unknown if it's a launcher or just a container, but I assume the latter.
- Flame Vent: Sprays flames on your enemies and coats your sword on fire.
- A fire-cracker attachment, used to scare and dazzle the enemy.
- Some kind of fireball-cannon, it's assumed that this is also the item that can enhance the main katana with a fire buff.
In the screenshots of the box-art we also see the protagonist with a second katana on his back, so dual wielding might also be a thing.