Fully upgraded, the 5 Chaos weapons outclass every other weapon in their respective categories. Aside from that, collecting all 5 is required for one of the easter egg achievements. The reason for this is that they’re hidden across the entire game in areas that can be difficult to find and are entirely unobtainable until you’ve beaten the game and acquired the Transfiguration Bloody Spells.If you haven’t yet beaten the game, then come back to this guide after you do.
You’ll need some Carved Stone Hearts and Lost Ancient Beads in your inventory to actually do the transfiguring. They can drop by defeating the enemies that you change in to, but I’d be shocked if you beat the game and didn’t have at least 3 of each one. Here are the 5 locations and the chapters/stages they correspond with. You can choose to load specific stages from the main menu.
Nightmare (Sword / Hammer)
The first Chaos weapon is located near the end of Chapter 3. You might have seen it locked behind a cell during your first playthrough, wondering what it was and how to get to it. Thanks to the power of Transfiguration, we now know. Most of this chapter is extremely similar looking, but this room stands out as it’s so large. Its most unique feature is its staircases to travel from the ground to the second floor.
This cell is on the second floor. From the angle pictured above, you can see how the bars to the right of the character are raised a bit off the ground. This is where Transfiguration 1 comes in, allowing you to take on the form of one of the dog enemies. Crawl through the gap and you now have the highest damage dealing weapon in the entire game. Pull the lever on the wall to save yourself a Stone Heart.
After you’ve passed through several collections of decrepit homes in Chapter 5, you’ll eventually follow a narrow path of shacks and crossbow traps to a stone wall that forces you to turn around and take an even narrower path further down. Don’t take that path. That stone wall has a small opening on the bottom (as well as several bear traps). Taking on dog form again allows you to sneak underneath the rocks into a very tight area where you’ll find my personal favorite of the Chaos weapons.
Follow along the right cliff face, down that narrow path I told you not to go down last time, and you’ll see a glowing clump of rock. This is where Transfiguration 2 comes in, allowing you to take form of a hulking demon that can smash through the wall. Do so and you’ll be rewarded with the third weapon.
Hellgate (Dual Halberd)
The Hellgate is literally right at the start of Chapter 9. Load in to the level and look to your left for more glowing rocks. With another demon smash, you’ll find a small cave with a treasure chest and the fourth Chaos weapon inside.
Demon face (Knuckles)
This final Chaos weapon is fittingly located in the final chapter. After fighting off the Priestess Phantom, look around the room for two green treasure chests. The one we want is to the right of the exit.
Sneakily hiding behind the chest is another small gap under the wall. By this point I trust you know what to do.
One last Transfiguration later and you should have a complete set of Chaos weapons. If you collected the complete set of Chaos armor later in this same chapter, then you’ll now be fit for anything this game can throw at you. You might have also unlocked a new skin for your character, which is truly the greatest reward out of this whole thing.
Find the untranslated blacksmith in Chapter 9. He’s found in various chapters, but the easiest location is here as he’s right after the start of the level on top of a rock formation. Bring him Iron Ore and select your gear of choice to begin the upgrade process.
The minigame here is to hold the left mouse button (or Confirm button on controller) until you think you’ve released enough liquid to fill the container on the bottom. You have to reach the green fill line. If any liquid crosses over the red line on the bottom of the screen, you’ll lose a try. You have 3 tries for each container. The strategy here is to count seconds in your head (one-one thousand, two-one thousand, etc,) and try to nail the amount required by the third try. If not, you just spend another Iron Ore for another three tries. You’ll get the hang of it pretty quickly.