I just installed the game and started playing singleplayer in multiplayer sessions because i want to be able to use my characters in LAN games (on the offchance that will ever happen).
My question is, since it's been a long time since I played this, are the quests only available in single player? Because i'm in the caves now and I have yet to get a single quest, well except the butcher quest. I recall a whole dungeon for the skeleton king quest and the poisoned well etc. but I can't get those quests it seems. I do find the skeleton king on the 3rd level surrounded by skeleton archers however but there is no quest that points to him.
Multiplayer games only get.... 4 quests, I think, whereas there are a total of 16 different quests in Singleplayer. The Butcher, The Skeleton King, Archbishop Lazarus, and Diablo are all you're going to see.
Also, there is no entrance to King Leoric's Tomb on level 3, he'll just be placed randomly on the level, so always be super careful around there when playing a new character.