Hellfire is an expansion pack that folds itself into Diablo, adding new monsters, items, quests, dungeons and a fourth playable character. The expansion tells the story of Na-Krul, a powerful demon imprisoned by none other than Diablo and now unleashed by a wayward mage. Hellfire has since been disowned by Blizzard, its storyline and characters denounced as being non-canonical.
This expansion pack adds two new dungeons: a hive-like structure thatís analogous to the Caves, located on the edge of town, and a crypt which holds Na-Krul himself, found near the Monastery graveyard. These two dungeons arenít immediately available as your character will either have to reach Level 15 or at least gain access to the Caves. In either case, Lester, the townís new expansion character who hangs around his herd of cows, will ask you to explore the Hive and clear it for him, triggering the first major expansion quest.