Diablo 3 update 1.0.5 will add a new Monster Power feature, which will allow players to tweak the difficulty of enemies to suit their desired difficulty. Many factors can be edited, from enemy health, attacking power and more, which in turn results in better loot drops. Blizzard has discusses the feature in greater detail.
Over at the Diablo 3 blog, community moderator Lylirra explained, “Similar to the “Players X” command in Diablo II, Monster Power gives Diablo III players the option to increase the health and damage of monsters according to different “power levels” – and in return, they’ll receive scaling bonuses to their adventure stats (including experience, Magic Find, and Gold Find) as well as more drops.”
“The option to adjust Monster Power will be available to all players starting at level 1 through the Quest Selection window, and can be adjusted separately for Normal, Nightmare, Hell, and Inferno difficulties.”
Here’s a chart of how different Monster Levels affect enemies:
The post goes on to explain that Monster Power level goes as far as level 10, and different settings can be saved per hero and difficulty, meaning you can customise enemies for each character.
Monster Power wil launch with patch 1.0.5 and applies to both single player and private multiplayer modes, and Blizzard is currently looking at the option for public multiplayer sessions.