Mighty Cyclops appears in the second half of the second section of the Tziah Block within Tartarus, from floors 151 to 163. It will always be alone and will be represented by a smaller shadow crawling along the floor.
Mighty Cyclops appears on the 9th and 10th floors of Marukyu Striptease within the Midnight Channel. In battle, they will alternate between casting Maragion and Physical attacks. They may also be supported by Killing Hand Shadows. Upon being defeated, it may drop the Sharp Thorn material. Selling 10 Sharp Thorns at Daidara will unlock the Kris Naga daggers for Yosuke Hanamura in the shop.
In Golden, it appears on floors 7 through 10. It may drop Lepidolite for trade at Shiroku Pub.