Every explorable area has an associated monster level. You can see the monster level of an area in the area map overlay, at the top right of the game screen.
Each area has a predetermined monster level, the value is not random. The monster level progresses fairly steadily as the player advances through the game. Areas in higher difficulties have higher monster levels than previous difficulties.
What it affects
An area's monster level determines the level of all of the monsters in that area:
- Normal monsters have the same level as the area's monster level.
- The level of magic monsters is monster level +1.
- The level of rare and unique monsters is monster level +2.
The level of a monster determines its various statistics, such as its maximum life, how much damage it deals, and so on. A monster's level also limits which affixes it can receive if it is magic or rare. For instance, the affixes that give a rare monster one of the damage reflection auras can only appear on high level monsters.
Monster level also determines the item level of any items that are found in chests in the area.
There is a penalty to the chance of currency items dropping in areas with a monster level more than two levels lower than your character level. See drop rate.