Sub-Monster are bigger than usual monsters, have different coloured aura and have special abilities. There are 6 of Sub-Monster, Regenerating , Speedy , Willful, Durable, Aggressive, Destructive. Each of them will start its name from 6 of these words (E.g.: Willful Goblin). All these sub-monsters only appear in Hard, Master and Abyss difficulty.
Type of Sub-Monster
Regenerating monsters have HP recovery, which heal themselves in certain seconds. They sometimes to be easy to kill because short of Max HP, and become harder because hgiher Max HP.
Speedy monsters are faster than all monsters, which have speed and attack speed bonus. Most of them are really hard because of fast speed and harder in small dungeons.
These kind of monsters have higher magic defense. They only recieves a little damage from players' skills.
Same as willful, but have higher defense instead.
Aggressive monsters will keep you attacking without being stopped themselves. Theses monsters must be killed first to get rid of death.
They are only ordinary monsters, but has greatest attack power. One damage will recieve a lot of damage to players.