Level: The Hilltop Mausoleum

Stained Glass Demon is the boss in the level "The Hilltop Mausoleum". At the end of the level you must push a block with fire under the blue heart of the Glass Demon. Then it spawns upstairs in a big circular room with a colored window in it.

Make sure you select your arm as a weapon for this fight. To do so, press Touchpad and X and "Arm". You are not allowed to use any other weapons or it will void the trophy! Arm only.

The Demon only takes damage when attacking its heart. It will only show its heart after launching some attacks at you. While it attacks, run away in circles around the room. All you really need to do is evade its attacks. When it shows its heart, the Demon will float in the middle of the area. The heart will float in the air. You can only hit it by throwing your arm with Circle. Each hit does 10 damage. The boss has 500 health total so that's 50 hits. On average you should be able to land 4-5 hits while its heart is showing. Then it will do a series of jump attacks again and throw darts at you, so run away and evade. Repeat the cycle until the boss is dead. If you're having trouble, come back later.

If you used another weapon by accident, don't worry! You can simply replay the level at a later time. The trophy isn't missable thanks to level replay functionality.