All that information was provided in Diablo's manual, both who each is and what their motivation might be.
The Warriors of the lands of Khanduras are well trained in all of the
weapons of war. Ranging from crusading paladins to unscrupulous
mercenaries, Warriors can be found wherever there is conflict amongst
their countrymen. Many of ...
I remember the Diablo I manual, as a wee child, detailing the backstory. Here are snippets from the manual:
THE DARK EXILE
“Seven is the number of the powers of Hell, and Seven is the number of the Great evils.”
Duriel, the Lord of Pain
Andariel, the Maiden of Anguish
Belial, the Lord of Lies
Azmodan, the Lord of Sin
As the ...
There are hints that the Rogue is the Blood Raven:
"My Rogue scouts have just reported an abomination in the Monastery graveyard! Apparently, Andariel is not content to take only our living.
Blood Raven, one of our finest captains in the battle against Diablo at Tristram, was also one of the first to be corrupted by Andariel. Now, you'll find her in the ...
Note I started putting together this list before you added the wiki-clause, I'm trying to corroborate this information with official sources.
There is an extensive timeline here and here. Neither seems to contradict each other so I'll just pull out the most relevant pieces of information from both.
It appears the above wikipages read from this page ...
35: Velen (W)
37: Fenix (S)
41: Imperius (D)
43: Blackhand (W)
44: Grommash Hellscream (W) - http://wow.gamepedia.com/Grommash_Hellscream
Grommash is a green orc, however in the alternative time line of WoD, he is red.
46: Mephisto (D)
53: Kel'Thuzad (W)
54: Kil'jaeden (W)
55: Archimonde (W)
58: Maive Shadowsong (W)
I'm 95% certain with this one,...
The Secret Cow level was spawned from the rumours of a Secret Cow level in the original Diablo game.
The Secret Cow Level is an Easter Egg; a funny bonus area in Diablo II that played on years of jokes about a secret level that could (supposedly) be reached in Diablo, by repeatedly clicking the cows found just outside of town.
There was no cow level in ...
The only portals mentioned in the various Diablo books I've read are demonic portals, not town portals (yet to read the Diablo III fiction). In fact Town Portal usage seems to be limited to the game.
If you're looking for a canon answer we can only extrapolate from the games themselves - since the monsters don't go through Town Portals in the game, we have ...
At present, no. Stay a while, and listen..
There is very little back story given to the inhabitants of Tristram, apart from the few that make it into the third game (one way or another). References to them appear to use the format provided by Valorum; [first name] the [occupation/title]:
Griswold the Blacksmith
Pepin the Healer
Ogdin the Tavern keeper
They weren't nearly as active as they were during the events of Diablo 2. Deckard even mentions that when the player shows up to the rogue encampment in Act 1. Areas change a lot after the Dark Wanderer passes through an area, and normally peaceful places become chaotic, and the monsters become a lot worse.
This is mostly due to the Dark Wander
Executive Summary: The destruction of the Worldstone had devastating physical effects to the Arreat Summit's immediate surrounds - turning it into a massive crater and poisoning the land. But it had a more interesting effect: with the Worldstone no longer actively reducing humankind's powers, they are reverting to nephalem with the associated powers that ...
In multiplayer in Diablo 2, access is party members only. Preventing those hostile to the caster from using the portal.
An argument can be made for extrapolating from there that the portals can only be used by those allied with, or allowed by, the caster, in either case preventing monster access.
As for the future of each character
The Warrior becomes the Dark Wanderer, eventually Diablo. Source.
The Rogue, is Bloodraven who is driven mad and becomes Andariel (the Act 1 boss).
The Sorcerer, is The Summoner who you fight in the Arcane Sanctuary in Act II.
This source speculates on the Rogue becoming Blood Raven, and the Sorcerer becoming The ...
The lore indicates that these gates (or the practice to create the gates) were created by the Horadrim
The Horadrim constructed numerous magical gateways between the mighty fortresses so that they could quickly concentrate their defenses against any incursion by the Demons. With but a thought, the Crusaders of the Light could transport themselves to ...
As the other answers state, the Lore was very much not present in the first game, but exploded in the second. The only hard link to any of the PCs actually being a character in the game's lore is Ogden's introduction:
Lore from the manual of Diablo II established that the warrior character from the first game was unknown to the village, despite Ogden ...
There are several things here to help patch up the holes in the plot.
Firstly, in-game, the name "Horadric Staff" makes it appear as though there is only one. There was more than one Horadric Mage, and therefore, more than one Horardic Staff (emphasis mine):
To safeguard Tal Rasha and prevent anyone from freeing Baal, the Horadrim sealed Tal Rasha within ...
Nothing seems to indicate that the "weakening" of the Nephalem was a permanent effect. Before the games, Uldyssian, a nephylem who was "awakened" by Lilith, alters the Worldstone, allowing the nephalem to regain their powers more quickly. He himself wields great power, and obviously his birth pre-dates his own alteration of the worldstone. In the end he ...
This page offers a publication history of the book series
This page offers an in-universe chronology of the book series.
What is important to note is that they do not have to be read in this [publication]
order. The only books that depend on previous books are the Sin War
trilogy (which should be read in order) and the Kingdom of ...
The three can can be roughly split by their schooling or status within the mage-clans.
Magi can be applied as a generic term or, more properly, to one of the mage-clans of the East.
Sorcerors do not have that official affiliation, but share the magi's training and use magic in a similar way. They can be thought of wandering magi.
Wizards are rogue ...
I haven't read the book, this answer is based only on the lore present in D2/D3.
Cain knows that (in D2) Andariel, Duriel, Mephisto, Diablo, and Baal were defeated. I believe that the Prime Evils' soulstones were shattered, but I'm not sure if the Lesser Evils have to have the same treatment for them to be 'defeated'. I say 'defeated' since we see their ...
To expand on the answer provided by AncientSwordRage, the backstory was retconned into Diablo 2; since there was very little provided in the first game. However, there were a few small hints (that Blizzard used to tie the story created in Diablo 2) that can be found in Diablo 1.
Firstly, King Leoric, and his son Albrecht were the first victims of Diablo. ...
From the Diablo III wiki:
The Dark Wanderer is established in background materials for Diablo II as the warrior from Diablo I. In the Book of Cain1, he is given the name "Aidan" and is revealed to be the the eldest son of King Leoric.
It appears as though Aidan took his group, possibly containing other Warriors, as well as the Rogue and Sorcer down to ...