The Monster Power system was introduced into Diablo III in Patch v1.0.5. This system allows players to custom set the difficulty and rewards they receive from monsters.
Full details have not yet been revealed, and there is no ETA for the patch to be released.
First Monster Power Mention
The system was first mentioned in a Blizzard developer blog tease on September 13, 2012.[1]
New System: Monster Power
Similar to the “Players 8” command in Diablo II, the Monster Power system is designed to give players more control over how challenging enemies are in each difficulty.
See the article in the Diablo II section of this wiki for full details about Players X. In a nutshell, it allowed a Diablo II player to simulate being in a larger game. More players in a game of Diablo II caused the difficulty to scale up by increasing monster hit points, as well as the experience awarded and items dropped. Players with powerful characters enjoyed setting their game to "players 4" or even "players 8" to turn up the experience gain and item drops commensurately.
Additional Details
More details were revealed in a pair of developer interviews in mid-September.[2]
- The Players X type system is known as “Monster Power” and players creating games can set it from 0-10 at game creation. You can not tweak it during a game, such as by turning it up before a boss fight.
- At higher levels the game difficulty is increased, with correspondingly better experience gain and item rewards. Details are still unspecified on just how they’ll be increasing the difficulty, and on what “better” items means. More, higher quality (Sets/Legendaries) items, higher level items, or all of the above.