intro

[Brogden]

Good news, I found more info. I got this off of a gamesurge essay:

Hidden Question -Shadowfang and Izual



The demon blade Shadowfang, was forced in the depths of hell, in the year -985. This cursed blade was a centre-point of demonic energies, and had the power to eternally corrupt and madden any mortal. Shadowfang was originally a massive sub quest planned for Diablo. This sub-quest involved a secret character named Tremayne the Priest, (which was removed from the game) and a powerful boss character named Fleshdoom. The quest storyline forced the hero to venture into Hellforge itself, in order to be rid of the demon blade. I believe that this quest was directly tied to another subplot, Izual the Fallen Angel. Izual and his Runeblade Azurewrath will be explained later. For now I will just say that both he and his powerful blade had a role in Diablo.

or it could be this:

Izual the Fallen Angel



During an attack on Hellforge in the year -990, Izual and his Runeblade Azurewrath were captured. The Prime Evil, Mephisto then tortured Izual. Tragically Izual fell to the powers of darkness, and became a Fallen Angel. His mind was altered and he became a loyal servant to the three Prime Evils.
Izual was originally a character involved in Diablo. Both he and his mystic blade Azurewrath remain partially implemented in Diablo. Izual has his own .wav sound file, which you can listen to here. The graphic for his blade Azurewrath is shown on the left. Most likely as you ventured through hell in your efforts to be rid of Shadowfang, you would confront Izual. Assuming that you battled with Izual, the battle would have probably been the hardest in the entire game. More importantly: would Blizzard have let you kill off this character? I strongly believe that battling Izual was a run off quest from Shadowfang. And I also believe that you would have battled against Izual before you confronted Diablo.

Izual says "Hows much does it take before you lose your grace mortal, let me show you." This implies that you would have indeed battles Izual. The only other thing we know about this battle is that it would have taken place in Hell, because Izual has been situated in Hellforge since he fell to the forces of darkness. This would have been a very interesting sub quest. It is a shame that enemies of this caliber were never introduced in the finished game, and this definitely hampered Diablo's overall gameplay.

that's supporting my current theory still.