On Google+ I had once raised the possibility of using ICRPG to play a tabletop version of the Diablo video game series. I would like to expand upon that idea a bit here.
What is Diablo?
Diablo is an action roleplaying computer game that focuses on hack-and-slash combat and loot acquisition in a dungeon crawl environment. Later games in the series expanded the purview of the environment to also include more “open world” environments, such as deserts, jungles, and snowy, mountainous landscapes. I personally prefer the focus of setting, theme, and story of the first game, which will be the focus of my thread.
What is the setting of Diablo?
The Diablo series is set in a gothic horror fantasy world of Sanctuary that has been brought into the conflict between the angels of the High Heavens and demons of the Burning Hells. Humans are the primary sentient inhabitants of Sanctuary and they frequently find themselves beset by the demons of the Burning Hells. Though humans are frequently aided by angels in their struggles against the demons, angels only do so begrudgingly, viewing humans as dangerous, easily corruptible potential pawns of the demons.
What is the story of Diablo?
The first Diablo game focused on the town of Tristram. The three Prime Evils of Hell (i.e., Diablo, Baal, and Mephisto) were banished by the lesser evils into the mortal realm where they were defeated by a group of wizards called the Horadrim. The Horadrim sealed the three Prime Evils into separate soulstones that they then scattered across Sanctuary. One group of Horadrim took the soulstone of Diablo and buried it deep beneath a monastery they constructed in a region of Khanduras, located on the western continent. The town of Tristram formed around this monastery. Over time the monastery fell into disuse with people forgetting the Horadrim, and the descendants of the Horadrim even forgetting their mission to safeguard the soulstone of Diablo, the Lord of Terror, at the bottom of the monastery.
Later, a warlord from the far east named Leoric conquered Khanduras and was persuaded by his priest, the Archbishop Lazaraus, to make Tristram his capital and to convert the monastery into a cathedral. It was at this point that Diablo began corrupting both King Leoric and Archbishop Lazarus, turning both into his pawns that would secure his freedom. Although King Leoric resisted Diablo’s possession, Archbishop Lazarus kidnapped Leoric’s young son, Prince Albrecht, and took him deep beneath the cathedral catacombs where his body became transformed into a vessel for Diablo. Diablo then filled the levels beneath the cathedral with demonic creatures ripped from the boy’s nightmares and transformed the dungeon’s lower reaches into a literal hell on earth. Likewise, Tristram became a town afflicted by the horrors and madness from beneath the cathedral. Intrepid adventurers have arrived to confront this evil beneath the town of Tristram but at what cost to their soul?
Why use ICRPG?
Diablo is a fast-paced point-and-click action RPG focused on loot acquisition. This pairs well with the fast-paced action and loot progression system of ICRPG. Loot can be found in the dungeon, easily used, and/or lost. Loot drives both game fairly easily. Though the PCs are heroic, they are not invulnerable, and the hellish dangers posed by the dungeon can make short work of the heroes unless they are careful and plan accordingly.
What would a Diablo-like ICRPG campaign need?
You can use the stats as they are, but I would personally simplify the stats of ICRPG down to four stats: Strength, Dexterity, Intelligence, and Willpower. Vitality has been a stat Diablo used, but these have primarily been used to determine HP which does not so readily apply to ICRPG. Diablo has variously used Magic (D1), Energy (D2), and Intelligence (D3) as stats. I would also recommend Willpower/Resolve as both a social and morale stat.
Along with that, FEAR mechanics. 
Though the computer game does not have any true mechanics representing the increasing madness and loss of sanity entailed in the Diablo setting, you can add fear mechanics for your Diablo ICRPG campaign. This may entail more general ability checks using Willpower/Resolve. But I would consider adding various types of fear-induced tags or conditions as a result of repeated failed checks could also work. Maybe players have a separate resource apart from their Hearts that they have to protect: maybe Brains/Minds/Heads. If a player has their sanity pool reduced to zero then the player hands the PC over to the GM because they have succumbed to madness and corruption. Who knows? Maybe your new character will later face your old PC who has now become a deranged cultist? Maybe you find an item that can increase your Sanity or your Health but not both. What will the PC decide is more important for their survival?
You could even include evil, cursed loot. If this loot has been stuck down in the catacombs and dungeons beneath the cathedral that have now been overrun by demonic forces, then how would you know that the loot is safe to use? Is there a price? Maybe you find a sword that let you use Ultimate on a 19-20, but each use takes a point away from your sanity or corrupts your physical form into a demoniac. Does it whisper wicked things into your ears?
What if I dislike the setting of Diablo?
Change it. In all honesty, I dislike the later lore developments that Blizzard made to the franchise, particularly post-Diablo 2. I would instead recommend making a game setting inspired by Diablo. Diablo is really just an excuse to do an epic mega-dungeon crawl beneath a corrupted cathedral, get cool loot, and defeat evil. It only offers a thin veneer of a story. Darkest Dungeons also borrows a lot from Diablo, and I would also recommend taking a loot at that video game for inspiration too.
I could write more, but I think that I will throw this out there for the time being.