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,...
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
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.
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
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 ...
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 ...
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 ...
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. ...