A monster with fifty heads and a hundred arms. Makes use of its hundred eyes for superior perception and its hundred arms for eradicating intruders. There are likely some who were so taken aback by its fearsome visage that they fled on the spot.
--Vita version bestiary
Hekatonkheires is a Sub-Boss that appears like a huge ball of faces surrounded by arms and spheres.
- Hekatonkheires does significant damage on contact with its body or surrounding orbs.
- It slowly flies toward the player through the walls and floors in the room.
The central heads.
- With 128 max health and the Knife, just get in and tank it. If you are quick, and don't run too close to it, you can kill Hekatonkheires reliably this way.
- You'll lose almost all of your health with this method.
The Hecatonchires, or Hekatonkheires ("Hundred-Handed Ones", Latinised Centimani), were figures in an archaic stage of Greek mythology, three giants of incredible strength and ferocity that surpassed that of all Titans whom they helped overthrow.  Each had a hundred hands and fifty heads, for the weilding of the destructive power of storm. 
If one looks at the map for Chamber of Extinction and Chamber of Birth, starting from the beginning of both respective maps, the player must travel the exact same distance and same path in the Chamber of Birth to locate the puzzle room requiring the Chakram as they must travel in order to obtain them in the Chamber of Extinction. This essentially means that the player finds the Chakram, in the Chamber of Extinction, in arguably the exact same place in the frontside field that it must be used in the backside field for it's puzzle in the Chamber of Birth. The rooms are practically back to back with one another.