Diablo, a very dominant demon, is the Lord of Terror and one of the Three Prime Evils of Hell, who had been confined in a Soulstone and repressed in caverns deep under the town of Tristram centuries ago by an early people known as the Horadrim.
Diablo got assistance from the exhaustively corrupt Archbishop Lazarus, who had been turned into his faithful servant. Nevertheless, for Diablo to really manifest himself in the mortal kingdom, he required a mortal vessel to house his spirit.
Diablo first tried to own King Leoric, the local ruler of Tristram, however owing to his declining state and the strong will of the King, Diablo as not able to get full control. Consequently, the demon unrestricted the King, Lazarus then kidnaps King Leoric’s younger son, Prince Albrecht. He puts him deep into the Catacombs where he puts the Demon’s Soulstone in the forehead of Prince. This let Diablo possess and warp the prince, thus attaining material form. Diablo may have a body now, but he is far from his full power.
The infuriated King Leoric blames the citizens of Tristram with the kidnapping of Albrecht, and has numerous people executed. The king’s dying words are a dreadful curse. In the meantime, Lazarus arose from the crypts and assembled the citizens, leading them deep into the catacombs to save the prince. This turns out to be a trap – in its place Lazarus takes them to the lair of The Butcher.
Entry of the player
This is where the player comes in. As he or she fights their way through sixteen levels to face Diablo, they encounter various monsters, quests, tomes, scrolls, weapons, and other miscellaneous items.
At the end of the game, the hero removes the soulstone from “Diablo’s” head. To the player’s surprise, Diablo begins to melt away, revealing Prince Albrecht’s body underneath. The hero then pierces his or her head with the Soulstone, attempting to contain the Lord of Terror. However, the end of the game hints at a darker outcome.
You pray that you have become strong enough to contain the Demon and keep him at bay. Although you have been fortified by your quest, you can still feel him, clawing his way up from the dark recesses of your soul.