What is the maximum party size (if there is one) in Diablo 3?
Additionally, how much of a buff do monsters get when adding party members?
"A new ally has joined, but the minions of Hell grow stronger."
What is the maximum party size (if there is one) in Diablo 3?
Additionally, how much of a buff do monsters get when adding party members?
"A new ally has joined, but the minions of Hell grow stronger."
As of the 1.05 patch on 10/16/2012, monsters gain a 70% HP increase for each additional character. So a 4-person Inferno party would face monsters with 210% more health than a solo character. (Prior to 1.04, the % increase per character was higher on higher difficulty levels).
Patch 1.08 reduces the HP-buff to 50% per player, resulting in a maximum of 150% more health.
This increase is applied AFTER any increase for monster power level. So at Inferno MP1 with one player, monsters have 150% hit points. With four players at MP1, they would have (150 * 3.1) = 465% hit points.
Update: There used to be a bonus to damage on higher difficulty levels, but it was removed in a hotfix on June 8, 2012.
The maximum party size is four people.1 2 There is no party experience split.3
For each additional party member, monster health scales: +75% HP in Normal, +85% HP in Nightmare, +95% HP in Hell, +110% HP in Inferno.4 5 (The upcoming 1.0.4 patch changes this. Instead of scaling monster health buffs with difficulty, all difficulties get a flat +75% HP increase per each additional party member.6) There are no other party size buffs.
Concerning the buff to monsters, as of 1.0.8 (currently in PTR):
Monsters currently[1.0.7] gain 70% extra health per additional player in the game. This is being reduced from 70% to 50%. This means in a two-player game, monsters have 150% as much health as a single-player game. In a three-player game, they have 200% as much health. And in a four-player game, they have 250% as much health (compared to 310% on live).