The franchise is set in the dark fantasy world of Sanctuary, and its characters are primarily humans, angels, and various classes of demons and monsters.

Other notable settings include the High Heavens and the Burning Hells, two separate realms with ties to Sanctuary.

The video game series' popularity and success has resulted in the publishing of several books relevant to the Diablo setting, covering a wide range of timelines of the universe.

[3] The universe of Diablo is divided into three realms: the High Heavens, the Burning Hells, and the human world of Sanctuary.

According to the backstory and lore provided by Blizzard Entertainment, Diablo functions as one of the seven Great Evils presiding over the Burning Hells.

[5] Two key characters who oppose Diablo in the series are Deckard Cain, an elderly scholar and the last descendant of the original Horadrim who serves as the core narrator of lore in the first three Diablo games,[6][7] and Tyrael, a member of the High Heavens' ruling Angiris Council who is sympathetic to humanity.

Though initially imprisoned, Diablo escapes and the Nephalem are perceived as a threat due to felling both angels and demons.

The setting of Diablo is the town of Tristram, the de facto capital of the Kingdom of Khanduras on the world of Sanctuary.

The actual fighting takes place beneath the town in a maze of dungeons, catacombs, and caves that lead into the depths of Hell.

The plot of Diablo centers around a player character undertaking a series of quests to free Tristram from Hell-spawned evil, descending through twelve levels of dungeons into Hell itself (the final four levels), where the player battles the title character, Diablo, Lord of Terror—one of the seven "Evils", demon lords who once ruled Hell.

The Monk fights best with staves or his bare hands and gains bonuses from wearing light or no armor.

Each of these environments contains various new monsters to fight, but they contain no random quests or bosses and the generated levels contain no shrines or libraries.

Players can choose from five distinct characters (seven when including the expansion) to control in their quest and explore the world of Sanctuary through four acts.

Diablo II: Resurrected, a remaster of Diablo II which also includes the Lord of Destruction expansion, was released in 2021 for Windows, PlayStation 4, PlayStation 5, Xbox One, Xbox Series X and Series S, and Nintendo Switch and will support cross-progression between the different platforms.

Instead of the previous skill selection system used in Diablo II there is an action bar at the bottom of the screen.

The skeletal undead under their command overwhelm enemies before they have a chance to strike, and the horrific curses the necromancers employ cripple even the most resistant of demons.

Necromancers can use their throngs of undead to create diversions, or to simply open a path for their master to escape to safety.

[22] Diablo Immortal was met with a negative reception from fans upon announcement for its creation as a mobile game,[23][24][25] and upon its release for the use of microtransactions.

The project was later moved to the original Game Boy due to the system's higher install base.

[32] It was planned to be released in three different cartridges in the style of the Pokémon games, each featuring a different class from original Diablo (warrior, rogue or sorcerer).

The project was developed from 2014 to 2016 and featured an increase in difficulty and an over-the-shoulder, third-person perspective, rather than the isometric style of previous Diablo titles.

Brevik was heavily inspired by the roguelike genre with turn-based combat, but with simplified role-playing game elements and a more expansive loot system.

Due to its procedurally generated maps and hack and slash nature, Diablo shares some similar mechanics as early roguelike games, though with real-time gameplay, graphics, and sound.

[43] The gameplay loop for Diablo games relies on a constant search for better weapons and armor, known as loot.

It features three stories: In November 2011, DC Comics started producing a five-issue miniseries (Diablo III: Sword of Justice) by Aaron Williams with art and covers by Joseph LaCroix.

[57] The games in the Diablo series on all release platforms have received generally favorable reviews from critics.

[81] Diablo placed #44 on a list of top 50 video game villains featured by Guinness World Records in 2013.

[85] Complex staff ranked Diablo 7th in their list of the 50 coolest video game villains of all time, describing the character as the "epitome of all evil comes in the form of a giant red behemoth that resembles the classic image of Satan as portrayed in most Judeo-Christian imagery, and he's one bad muh.

[87] In May 2021, Blizzard Entertainment commenced legal proceedings against Fox Media in a dispute over the trademark rights for the name "Diablo".