Diablo Quest:

Quest :Butcher

Quest Giver : wounded Townsman outside the Church

Single + Multiplayer

How to do it :  Go down to Level 2 and find a Bloody Room open the Door and slay the Butcher

Reward: Single Player : Butchers Cleaver  MultiPlayer: a Magic Item

Quest: King Leoric

Quest Giver : Ogden

Single + Multiplayer

How to do it :  Singleplayer : Find the entrance to Leorics Chamber at Level 2 or Level 3 go down and kill him

Multiplayer : Leoric is in the 3 Level of the Dungeon

Reward : Single Player : Undead Crown an Unic Item

Multiplayer : a Magic Item