Diablo Wiki
Developer(s) Synergistic Software
Blizzard North (executive producers, playtesters)
Blizzard Entertainment (playtesters)
Publisher(s) Sierra On-Line
Series Diablo
Released November 24, 1997
Genre(s) Action role-playing game, hack and slash
Mode(s) Single player, multiplayer
Ratings ESRB: M (Mature)
PEGI: 16+
ELSPA: 15+
KMRB: 18+
Platform(s) Microsoft Windows
Media CD-ROM
System requirements Windows
Windows 95 or better, 60 MHz Pentium or better, 8 MB RAM (16 MB for multiplayer), SVGA-compatible graphics card, 2X CD-ROM drive
Mac OS
Power Macintosh or compatible, 8 MB RAM with virtual memory, System 7.5 or higher, 2X CD-ROM drive
Input methods Keyboard, mouse

Hellfire is an expansion pack that Sierra On-Line (now known as Sierra Entertainment) produced for the computer game Diablo. It was released on November 24, 1997 and developed by Synergistic Software, a Sierra division.

The expansion was re-released on GOG.com in June 2019.[1] On 29/30 January 2024, the base game along with the Hellfire expansion released on Battle.net itself and can be installed via the Battle.net desktop app.[2]


Hellfire's storyline occurs in parallel to the main story arc of the original game. A Sorcerer, while performing a ritual, inadvertently unleashes the demon Na-Krul upon the town of Tristram, but before it can completely escape, the Sorcerer magically seals the doors. The player is later tasked with venturing into Na-Krul's lair and vanquishing it.

Na-Krul being summoned into Sanctuary

The expansion pack adds several enhancements to Diablo, including an additional Monk class, two new dungeon settings – namely The Festering Nest and the Demon Crypts – additional quests to undertake, several extra game items – including oils which affect item statistics and runes that can be placed as traps – a new page of spells, new affixes for weapons and armor, new shrines, new mini-boss enemy names, a noticeable boost to Diablo's strength and power, and a number of interface improvements.

Hellfire integrates into Diablo, and because of its design, its new quests and dungeons do not have to be tackled to complete the original quest to slay Diablo. In order to gain access to the dungeons, the player must speak with Lester the Farmer, who is north of Tristram, near the herd of cows. However, if the player speaks to Lester before reaching either character level 15 or the Caves portion of the main quest, he will be hesitant to ask them to enter the new dungeons.

The rest of the expansion integrates more fully into the main adventure. Objects like oils, new weapons, rings and armor, and runes drop amid other more common kinds of items, and the new spellbooks, including books for two previously existing spells that did not have books, and scrolls are found in the same kinds of places. New shrines are found where shrines would normally be found. The new unique monsters, which appear as palette-swaps of normal monsters with unique names, also integrate in the main Diablo quest. It should be noted, however, that there are almost no unique monsters found within Hellfire's exclusive dungeons. The Hellfire dungeons are populated with new enemies that do not appear in the main Diablo quest, however. The difficulty of Hellfire dungeon floors 1-8 are is comparable to that of levels 9-16 of the main Diablo quest, requiring experienced characters to explore.

Some of the newer convenience features include the option to move more quickly around town using the "jog" toggle found in the options menu, a spell that highlights objects lying on the floor as though the cursor was placed over them, and a spell that teleports the player to the nearest exit found on that level of the dungeon.

Hellfire is the only expansion pack released for Diablo. Blizzard Entertainment has never released an official expansion of its own.

Hidden Characters and Quests[]

Two additional characters, the Bard and Barbarian, and two additional quests can be enabled with a special text-file edit in the Hellfire installation directory. This is accessed by modifying the Command.txt file.

As test characters, these classes have new skills and attributes. The Bard can use two one-handed weapons, one in each hand. The Barbarian can hold certain two-handed weapons in one hand and carry a shield in the other. They do not have unique character graphics developed for them, appearing in-game as the rogue and the warrior, respectively.

The hidden quests are the Theo quest and the cow quest. The cow quest appears first by turning Lester the Farmer, who allows the player to unlock the hive, into the "Complete Nut", who wears a cow suit. After giving the player a rune bomb to open the hive level, he will send the player off to recover his suit. Once the player returns the brown suit to him, he rewards them with the Bovine Plate. There is also a Grey Suit item in the hive level that the complete nut will reject as "too formal". The cow quest was based on an Internet rumor/hoax that directed players to complete a series of silly objectives to unlock a secret cow level.

The Theo quest is given by a little girl standing by a tree near Adria's shack. The player must kill the Hork Demon to retrieve Theo and acquire the reward. If this quest is not activated, the Hork Demon drops the amulet himself with no diverting storyline.

There is a special floor tile in the Crypt dungeon that is in a room by itself; when the player steps on it, a voiceover and text explain that the player has found "The Cornerstone Of The World" where the boundary between worlds is weakened. In practical terms, this means that when an object is dropped on this tile, it will appear on the Cornerstone tile of all of the player's save files, allowing the player to transmit items one at a time between their own saved games. This was implemented to account for the frustrations of random item generation when, for example, one's Sorcerer finds a really nice axe it can't even hold that one's Warrior or Barbarian could make better use of.

There is also a cut character that cannot be restored with the Command.txt exploit, the Wandering Trader.


The Hellfire storyline is not acknowledged in Diablo II. It was not released as a part of the Diablo Battle Chest, but did receive its own Diablo/Hellfire bundle, published in 1998 by Blizzard Entertainment. Consequently, Hellfire's status in Diablo canon is unclear.

However, in Diablo II, Blizzard North later implemented insect caves and crypts that bear similarities to those in Hellfire. A few of the convenience features introduced in Hellfire were also added in Diablo II as fully-fledged functions, such as being able to run to cover ground more quickly and being able to highlight items lying on the floor by button press (Alt by default), instead of by spell.


Hellfire received generally favorable reviews from game magazines at the time.[1] It was Synergistic's most financially successful release.[3]


Criticisms of the expansion include:

  • The atmosphere of the new quests and dungeons was not as compelling as that of Diablo.
  • Some new spells were merely modifications of existing spells, such as Lightning Wall, Ring of Fire, or Immolation.
  • Hellfire had no support for Battle.net, the online service utilized by Blizzard's online multiplayer games.
  • Incompatibility with the Macintosh version of Diablo.
  • A rushed development cycle.
  • Many of the later bugfixes introduced in patches for Diablo do not carry over into Hellfire, and Sierra only released one patch, fixing a small number of bugs exclusive to Hellfire itself.



Blizzard North did not develop an expansion to Diablo, instead opting to make a sequel. For Blizzard North's parent company, Sierra On-Line, this was seen as "leaving money on the table", given that any expansion could work with the game's already existing code. Given Diablo's critical and commercial success, it was predicted that expansion sales would easily dwarf production costs. Synergistic Software, which was under the same Comp-U-Card International (CUC) umbrella that its parent company was, was asked if they could make an expansion in six weeks, to which the answer was "yes". While the job was technically passed onto Sierra, it was Synergistic that would carry out development.

Differing accounts exist as to how Blizzard North and Blizzard South reacted to the news of an outside company developing a Diablo expansion. Some parties recalled the two Blizzards being told ahead of the project’s start date that an external studio would be developing an expansion pack for Diablo. Others remember CUC’s executives flying under the radar to green-light an expansion. One programmer claimed that the expansion had to be done before Allen Adham returned from vacation, as he'd be dead set against an expansion for Diablo. But whatever the timing of the matter, the heads of both Blizzard North and South reacted negatively to the news. The protests were ignored and development moved ahead. Blizzard North agreed to help development on the condition that they serve as executive producers and have final approval on everything.

In the early spring of 1997, Householder flew Hellfire's developers to Redwood City for a meet-and-greet. The meeting between Synergistic and Blizzard North developers was cordial. A key direction from Blizzard North was that, as they were working on Diablo II, they didn't want Hellfire to overlap—spells, themes, etc. A set of guidelines were established:

  • Only one new character class could be created (a Barbarian class couldn't be created, as Blizzard North was saving that class for Diablo II)
  • Eight new dungeon levels could be created between two new environment types
  • Two new music tracks could be developed
  • New items and spells could be implemented
  • No multiplayer (as this would require re-balancing the game)

To kickstart development, Blizzard North granted Synergistic access to Diablo's code and gave lessons on how to create characters and tiles using the software. Synergistic was open to most of the guidelines bar the "no multiplayer" rule. There were fears from Blizzard that if the game was poorly balanced, this would negatively influence reception to Diablo proper. Synergistic itself had no experience in designing multiplayer games; this rankled some of the developers. In the meantime, CUC extended the production deadline to four months.[3]

Active Development[]

Because of the tight development schedule, features from Diablo that could be "fixed" were given priority. One of them was the slow walking speed in Tristram. To fix this, Synergistic introduced the "jog" mechanic, which doubled players' movement speed while in town. As it turned out, Blizzard North had tried to introduce a similar mechanic in the base game, but couldn't animate it to their satisfaction. The "jog" function of Hellfire operates by simply skipping every other frame of the walk animation. The second adjustment was the auto-heal function, where Pepin would fully restore players' Life automatically once clicked upon. This would become standard in all future Diablo games.

The Bard and Barbarian were conceptualized early in development, but dropped in favor of the Monk.

The leaders of Blizzard North often spoke up when they perceived Hellfire as clashing with Diablo's setting and tone.

Synergistic completed development ahead of schedule and submitted Hellfire for approval. Both Blizzard studios weighed in on submissions. According to Synergistic's developers, North was easier to please than South, whose artists took umbrage with what Hellfire's team perceived as quibbling issues, such as an off-color pixel in one corner of the screen that needed to be changed to match the others. Both studios carried out play-testing. Reportedly, South found more issues than North. In the downtime, Synergistic added additional material to the game, such as new quests and Easter eggs. When both South and North learned of the Easter eggs, they demanded that Synergistic remove them. Sierra was adamant that the game would ship, but pressured Synergistic to appease Blizzard South as much as possible. Some of the Easter eggs were removed, but others remained hidden.[3]

Patch 1.01[]

This patch provides fixes and enhancements to the Hellfire 1.00 product. It provides a new executable (HELLFIRE.EXE), an interface library (HELLFRUI.DLL), a patch text file (Patch.txt), and a version text file (Version.txt.)

List of Changes:

  • Fixed Gossip (same gossip from each townsperson every time)
  • Fixed disappearing quests (upon re-entering the town level, quest statuses were incorrectly cleared through array bounds overstep).
  • Fixed generating spell books by Adria (would "morph" on new game).
  • Fixed the bug where picking up gold when your inventory is full duplicates the gold in your hand and fills your gold slot.
  • Fixed the Berserk spell to prevent crashes (large numbers of berserk monsters occasionally attacked dead monsters).
  • Fixed inactive monsters to prevent same kind of crash as above
  • Fixed entering levels; had crashed on some systems (seemingly randomly).
  • Fixed doppelganger's items to not clone Diablo
  • Fixed generating rings of fire behind a wall.
  • Sped up monk's open-hand attack (users complained he should be faster with barehanded attacks than with the sweeping staff).
  • Various small internal fixes to prevent potential misbehavior.
  • Fixed monster hitpoint variable type for tough monsters (some monsters, especially in Nightmare/Hell difficulty, had way fewer hit points than specified)
  • Changed Search spell to show items on automap, too (users complained they couldn't find things behind solid walls in Caves, Nest, Crypt).
  • Fix to unique items changing between games (Veil of Steel, Arkaine's Valor, etc.).
  • Fixed to dropping and picking back up oiled items (bonus was lost).
  • Fixed Cathedral Map activation crash bug
  • Added sounds to Mana Drain and Disenchant traps
  • Monster hit points in Nightmare/Hell are +100/200 instead of +1.5/+3
  • Fixed monster stats display in Nightmare/Hell to reflect the halving.
  • Balance/Stability/Harmony now does something


  1. 2019-06-05, GOG Diablo Now With Hellfire Expansion. Blizzplanet, accessed on 2019-06-13
  2. 2020-01-30, Face the Lord of Terror in Diablo, now available on Battle.net. Blizzard Entertainment, accessed on 2024-01-30
  3. 3.0 3.1 3.2 2018-06-29, How a Diablo expansion led to behind the scenes trouble. Polygon, accessed on 2018-06-30