Inferno (difficulty)

Inferno was the fourth, final, and hardest Difficulty in Diablo III, even more challenging than Hell.

The lowest monster level found here would be 61, which was 1 level higher than the level 60-cap for player characters in vanilla game. Monsters would increase in power by 1 additional level for every Act, up to level 63 in Act III.

At some point, this was changed to level 63 in all Acts.

In addition, Life Steal was would be reduced by 80% compared to Normal difficulty.

Eventually, this difficulty was removed. Torment is the closest equivalent to it as of 2.0.

Inferno was presumed to be the highest, most challenging difficulty in the history of Diablo series; however, it took less than 5 days for a player by the name of Sygodoeden to beat it (by killing Diablo), followed closely by a group of 4 players from Method. It took roughly 6 weeks to do same on Hardcore.

Inferno difficulty had unique rewards that could only be found in that difficulty.

Development
Inferno was designed for players who had hit the level cap. Upon the release of Diablo III, and the mixed player reception, Inferno mode was looked at, and a problem identified. The game's best gear only dropped in Inferno mode, but for many players, the game couldn't be beaten without said best gear, creating a chicken-and-egg scenario. The Auction House provided a means of getting the gear required to succeeded in the mode, but many players were reluctant to use it, let alone part with real money.