The one-eyed and the hundred-eyed shall appear. Return with the one-eyed and the hundred-eyed shall lose its strength. Beyond that lies everything.
--Endless Corridor (C-5) Tablet
Has one huge, round eye and numerous hair-like branches growing from its body. Can change its body size at will, allowing it to travel the world and watch over humans.
--Vita version bestiary
Backbeard is a Sub-Boss of the Endless Corridor. It appears as a floating black mass of shadows and tentacles, with a large red eye at its center. Only when it is defeated is its companion sub-boss, Tai Sui, vulnerable to attacks.
When you first read the Tablet in (C-5), Backbeard appears but cannot be harmed. To damage it, you have to travel all the way to the right to (B-5), place a weight on the dais that appears there, then travel back left to (C-5) and place a second weight on a new dais. After the second weight is placed, Backbeard can be fought. The trip back and forth must be done while Backbeard is present and chasing you.
- To make the trip easier, you can clear all the normal enemies from the 5th floor before reading the Tablet that summons Backbeard.
- Ignore the big pile-of-eyes monster Tai Sui in (B-5) for now.
The red eye, when it is open. It might not take damage if it is almost closed.
- Get Backbeard to chase you to an area with enough space to run away from it and jump over it, like the starting room (C-5).
- Face it so that it will freeze and you can position yourself within weapon range.
- Turn away from Backbeard, then quickly turn back and strike when its eye is open.
- As soon as you turn back to face it, it will start to close its eye. This might take some practice.
- The more room you have in front of you, the more times you can do this before having to jump over it.
- 5 hits from the Axe+randc.exe+mekuri.exe combination kill it
- Backbeard can be trivially defeated by allowing him to approach you as detailed above, then using the Lamp of Time and attacking it while it is frozen. This is especially convenient due to the Nebra Sky Disk at A-5
- Backbeard can also be defeated by using the Caltrops. Run in a circle over and under the platform in the middle of the room, constantly dropping caltrops that Backbeard will obligingly run into with its eye open.