Instructions
Move around the room to avoid Gleeok's projectile attack.
Approach one of his heads from the left or right side and slash it once with your sword. Move away to avoid his next projectile attack.
Continue this method until one of the heads comes off. Continue to move to avoid all projectile attacks and slash the remaining head in-between each projectile volley.
Follow this pattern to attack the remaining head with your sword until it is removed to defeat Gleeok.