Normal : Monsters that came into existence without external influences. Mutant : Mutated form of normal Monsters. Demon : Monsters of the devil which evolved from Normal, Mutant or Undead. Undead : Magical monsters resurrected from a dead body. Mechanic : Monsters having much stronger aggression than Demon.
Level 91-100
Grotesque
Level : 100
HP value : 15,000
EXP value : 50,000
Found In : Railroad of Chaos
Part of it's body have mechanical parts that was given by the Midranda. They are awesomely powerful.
Ratoo
Level : 100
HP value : 7,000
EXP value : 59,000
Found In : Cursed Temple 2nd Floor
The Ratoo is said to have been bred by the Guardians of the Gods themselves. The Ratu has four legs and powerful claws. On one hand it has a powerful cursed weapon called the Choas Scythe. They have been in loyal service for centuries, awaiting their freedom.
They reaped many victories in past wars but their awesome strength made some of the gods apprehensive which caused them to be imprisoned. Even now, when their strengths have diminished, only the most powerful warriors are allowed to enter into regions where the Ratoos are known to appear.
Normal : Monsters that came into existence without external influences.
Mutant : Mutated form of normal Monsters.
Demon : Monsters of the devil which evolved from Normal, Mutant or Undead.
Undead : Magical monsters resurrected from a dead body.
Mechanic : Monsters having much stronger aggression than Demon. 
