I have seen some low level players have difficulty in killing Cyclops. From watching this video tutorial, I hope you can figure out a way to kill it when you are at low level or playing different class.
Three attack patterns from Cyclops:
1. Basic attack
2. Basic attack + moon slash + lava wave
3. Moon slash x2 + moon slash (Rage mode)
*Lava wave causes the most damage, may be up to 4/5 of the health bar
Music: "Protectors of the earth" by Two Steps From Hell