Changes

The D3 team has created a huge variety of monsters for our slaughtering pleasure, and the denizens of the underworld are customized, personalized, and quite versatile. Bosses have been greatly upgraded in appearance and size, and the AI has been improved as well.

It's not yet known how monsters are classified in ''Diablo III''. There are monsters seen in the early screenshots and gameplay movie that look to be animals, and quite a few undead, and others that might be demons, but there's no telling if that ''Diablo II'' classification system will be reused in ''Diablo III''. We're tentatively referring to the monsters by their apparent demon/undead/animal genus, for the sake of easier organization, but do not take that as evidence that they'll be sorted by those types in the game.