Brilliant Cyclops is a boss found on the 9th floor of Cocytus withing the Abyss of Time and must be beaten to continue. During battle, it will attack using Ice spells with the occassional physical attack. After taking some damage, it will begin summoning Soul Dancers as backup and start using its Bufudyne skill. After being defeated, it will drop a Broken Wheel which can be used as a barter item.
Brilliant Cyclops may be found in the 6th World of Magatsu Mandala within the Midnight Channel. It will alternate between physical strikes and Primal Force. After being defeated it may drop a Cruel Thorn. Selling 6 Cruel Thorns will unlock the Blitz Knife for Yosuke Hanamura in the shop.