In here, there are five locked doors that require a special key for each. They all hide weapons, and unless you managed to pick any during your first playthrough, it’s likely that you’ve missed them all. But don’t fret! We’ve got you covered.
Factory - Prism Key Location
This one is very straightforward.
When you start the game (or just go back using the chapter selection screen), deflect the first bullet and then continue doing the tutorial.
Once you can jump, get on top of the building nearby, and start making your way until the beginning of the level.
You’ll see a dead body laying in the left corner. Approach them and interact once the button prompt appears to get the Prism Key.
The Prism Key enables a flashy new Prism Sword in the Government Lab. The description reads: “The world is your canvas and the world is the paint.”
Hotel - Master Key Location
You’re gonna want to head to the third checkpoint, right before the final interaction with the NPC on the rooftop.
In order to get here, you’ll have to go through a couple of stages that shouldn’t give you too much trouble.
When you arrive at the location of said encounter, which has two enemies in a room right before it, you’ll want to take them down using melee and save a throwable weapon in your inventory (the head statue is perfectly placed for this).
Once that’s settled, open the door to the rooftop. As soon as you start walking, throw the object to kill the enemy before he jumps. Get near the body and loot him to grab the Master Key.
This key will open the second door, which holds the Sword of Masters. The description says: “Shoots an otherworldly beam when charged,” which is pretty self-explanatory.
Prison - Prototype Key Location
The Easy Way
You can get this key much easier by simply refusing to take your medicine before the mission. If you completely refuse to take your medicine, you will be told to kill everyone on sight. Do it.
Once you’re done with the mission and talk to the veteran, kill him. After that, you’ll be able to get the key from a suitcase back in your apartment building.
The Hard Way
Doing it this way is far more difficult and not recommended.
First, you’re gonna want to go to the second checkpoint of the Prison chapter, locate the target’s body, and wait for the police to show up.
Now, you’re gonna have to spend some time in some cells until you’re able to exit without killing a single guard.
Make sure to hide inside cells while you wait for them to pass, and make use of stairs to stay out of sight. This should take you a few tries, but it can be done in a few minutes.
When you get to the level where there’s only one enemy, enter the door. There, you’ll be able to see the guard’s location by looking at the screen.
Once he’s on the right side of the room’s entrance, exit and get out of there.
Now, this last part might seem complicated with so many lights around.
Just make use of the tables and objects around. For the former, you’re gonna have to crouch for the stealth to become effective (you can tell by the eye above the character).
Once you finally exit, you’ll get to the cutscene and dialogue with the veteran. The key will be in a suitcase in your building, just as with the other method. With it, you can get the Claymore Prototype.
Mansion - Phoenix Key Location
In the Mansion Chapter, select the second checkpoint and start traversing through it.
You’ll come along an expansive area where you can see a thief-like character on the upper left corner. Don’t engage, instead take care of all the other enemies in there.
After you’ve finished, stay in the room right before the thief, and wait for him to leave. As soon as he escapes through the window, go inside the room and grab the Phoenix Key from the ground.
This will unlock the Phoenix Edge, which reads “Cuts through foes with the phoenix’s flame slice.”
Slaughterhouse - Savant Key
This one might seem complicated at first, but there’s a way to bypass the tests and focus on getting the key. In fact, that’s the only way to actually retrieve it, so make sure to follow these steps.
Once you get to the first room with a giant screen, open the door, lure the enemy to you before killing him, and them do an aerial attack on the wire at the left side of the TV.
Keep going through the levels until you find the open test area. You’re gonna want to use the roll as many times as possible as you exit the room. Do the same on the next one, head down, and approach the barrels.
You’ll find the Savant Key here, which unlocks the final blade: Savant Knife, “a short blade with an extremely quick attack”.
You’re probably wondering that’s hiding in the sixth door. Me, too. Apparently, this will hold a future DLC, although the studio hasn’t revealed any release dates for the time being. If you want to know more about Katana ZERO, make sure to read our Katana ZERO review.
