If the level of the person who made the greatest contribution is higher than the level of the raid monster by 3 or more levels, then the probability of dropping an item or adena will decrease. If the level difference is nine or more levels, then, the monster will not drop any item or adena.
Raid Boss - Level 53
Mutant of the powerful Monster Eye. Some call it the final feature of Monster Eye's evolution. It has superior intelligence and strong pride. It ran away from Argos, the father of all Monster Eyes, to the south, but has the ambition to grow its power and take over the power of Argos someday. It believes that it gets stronger by eating the brains of other intelligent living things.