The Monster Power system was introduced into Diablo III 3 in [[Patch v1.0.5]] in October 2012, after being testable on the Diablo 3 [[Public Test Realm]] for several weeks. Inspired by the Diablo 2 {{iw|Players_X Players X}} system, Monster Power allows players to set a level from 0-10 which will increase the difficulty of the game. [[Patch 1.0.7]] updated Monster Power to add considerably more experience per MP level, making for faster leveling up with higher MP levels.

The rewards and scaling values differ from Normal/Nightmare/Hell vs. Inferno, and playing on even MP1 in Inferno increases all Act 1 and Act 2 monster levels to 63, creating a big leap in difficulty and item drop potential, especially in Act One.

Blizzard released full information about the Monster Power effects in mid-October 2012, detailing the exact changes triggered with each level of Monster Power with the aid of some infographics. Note that the v1.0.5 patch also contained a substantial nerf to overall Inferno difficulty, thus MP0 in v1.0.5 was considerably easier the game had been previously, and Blizzard estimated[http://diablo.incgamers.com/blog/comments/more-details-on-the-monster-power-system] that MP2-3 was about the equivalent difficulty for pre-v1.05.

Note that the v1.0.5 patch also contained a substantial nerf to overall Inferno difficulty. Playing the game on MP0 in v1.0.5 is considerably easier than it was in previous patches.  Blizzard estimates[http://diablo.incgamers.com/blog/comments/more-details-on-the-monster-power-system] that MP2-3 is the rough equivalent of v1.0.4's difficulty, though this varies considerably between acts. That equivalency is generally true for Acts 3-4. It's not true for Acts 1 and 2, since the monsters increasing from mlvl 61 and 62 up Player testing tended to 63 makes a big difference in difficulty, as players discovered with early play testing.disagree[http://diablo.incgamers.com/blog/comments/v1-0-5-testing-level-1-on-monster-power-10]and at least in Act 1 and Act 2, the game felt harder on MP1 than it had been previously.

[[File:Monster-power-bonuses2.jpg|center|thumb|800px|Monster Power on the [[Inferno]] difficulty, v1.06.]]

The key factor not shown in this chart is Patch v1.07 considerably increased the fact that '''all''' monsters on Inferno instantly become experience gain per level 63 (the highest level possible for non-bosses) at Monster Level 1 or , making higher. This effects many game features, and makes them much harder to stun, chill, freeze, knockback, etcMP levels more rewarding.

It also boosts their item * MP 1: 25% (up from 10%)* MP 2: 50% (up from 20%)* MP 3: 80% (up from 30%)* MP 4: 120%(up from 45%)* MP 5: 165% (up from 60%)* MP 6: 215% (up from 75%)* MP 7: 275% (up from 95%)* MP 8: 340% (up from 115%)* MP 9: 420% (up from 135%* MP 10: 510% (up from 160%)  A key factor for players new to the MP system is the fact that playing on even MP1 raises the monster level drop potential greatlyof all enemies in Inferno to 63. This changes nothing in Act 3 or Act 4, but on MP0, Act 1 = 61 and basically "flattens" the Inferno difficultyAct 2 = 62. Monsters at level 63 have much better odds to drop higher level gear, granting the monsters but are also much more difficult to battle in each act the potential some ways, especially regarding their resistance to drop the best items in the game[[crowd control}CC]] effects such as stun, chill, knockback, etc.

As you can see in the infographic belowabove, there is no change to the item level potential of drops in Act 3 and 4, but with ML1+ monsters in Acts One and Two drop items with the same high level potential as Act 3 and 4.