Diablo II was one of the most popular games of 2000. Major factors that contributed to Diablo II’s success include its addictive gameplay and access to the free online play service, Battle.net.

The game was conceptualized and designed by David Brevik and Erich Schaefer, who with Max Schaefer acted as Project Leads on the game. The main production roles were handled by Matthew Householder and Bill Roper.

An expansion to Diablo II, Diablo II: Lord of Destruction, was released in 2001, and is currently at version 1.13c. A sequel, Diablo III, was announced in 2008.

The storyline of Diablo II progresses through four acts, with each act following a predetermined path and list of quests. Some quests are optional. The player assumes the role of a hero from one of five different character classes. Players fight monsters through wilderness areas and dungeons in order to level-up their character and gain better items. Combat is in real-time, and shown from an isometric viewpoint. Players also have the option of hiring one of several computer-controlled mercenaries, or hirelings, that follow the player and attack nearby enemies. A powerful boss monster awaits the player at the end of each act. Item drops, monster attributes, and most dungeon layouts are randomly-generated by Diablo II.

In addition to the four acts, there are three sequential difficulty levels: Normal, Nightmare, and Hell. On higher difficulties, monsters are stronger and are resistant to an element, experience is penalized on dying, and the player’s resistances are handicapped. A character retains all abilities and items between difficulties, and may return to a lower difficulty at any time.

Players can also create a hardcore character. In softcore, the player can resurrect their character if killed and resume playing, while a hardcore character has only one life. If killed, the character is permanently dead and unplayable, and all items and equipment on that character will be lost unless another friendly character has the “loot” icon checked.

The story of Diablo II takes place some time after the end of the previous game, Diablo, in the lands of Sanctuary. In Diablo the main body of the story takes place beneath the floors of a cathedral in a small town known as Tristram. It is here that Diablo, the Lord of Terror, is defeated by an unnamed warrior after many previous battles are also won.

The unnamed warrior that vanquished Diablo drove the demon’s soulstone into his forehead, in an attempt to contain the monster’s essence within his own body. Later in the canon it is suggested that this is what Diablo intended so that, should he be defeated, he had an “escape plan” in place of dying.

The unnamed warrior is ill fated from the moment he does this and is gradually corrupted over the course of the next few days by the demon’s spirit. Deckard Cain recounts the story to the next band of adventurers that pass through the Rogue Encampment in Diablo II. It is one of these adventurers that appears in the wake of the destruction caused by the now possessed unnamed warrior, and attempts to find out the cause of the evil, starting with the corrupted warrior (known as the Wanderer throughout Diablo II).

As the player continues through each of the four acts, he faces off against two of the Prime Evils (Mephisto – Act III and Diablo – Act IV, with Baal, the last prime evil, being the main boss in the expansion pack i.e. Act V), and two lesser evils (Andariel – Act I and Duriel – Act II), who act as minor bosses for the first two acts. The player learns of the truth behind the corruption and the story of the soulstones. Diablo released Mephisto (Lord of Hatred) and Baal (Lord of Destruction) from their soulstones, as they were taught long ago how to corrupt them by the fallen angel Izual (also a minor boss in Act IV).

In the end, the player eventually reaches and slays Mephisto and Diablo, in their respective Acts. The story continues in the expansion to the game, where the player chases the last of the Prime Evils: Baal, who is going after the mythical Worldstone in an attempt to corrupt it.