Cosmic Star Heroine
34 Achievements
10-12h
Eldritch Master
Defeat a cosmic entity.
52.0%
How to unlock the Eldritch Master achievement in Cosmic Star Heroine - Definitive Guide
MISSABLE
Optional Boss
The trophy is obtained by killing the optional boss Cthulhu. He is very strong and has 90,000 HP and should not be fought until you reach the point of no return.
Once you are near the end of the game or at the point of no return, travel to New Rhomu. He's is located in the desert area south of a town on New Rhomu. Once in the town, head over to the east side of the town then travel south and leave the town. Keep heading south, then travel to the left when you get to the sign "<- Zanzaran mines." Exit the screen and continue south and then right in this area. Cthulhu's lair is here. Enter the tomb and fight him. The trophy will pop once he is destroyed.
See video for more detail.