The Darkening of Tristram

"The past is never far in these parts... Cultists have delved through the remnants of Adria's belongings and discovered the secret to reviving her memories. For a fleeting time, this town will appear as it was many years ago..."

- In-game description

The Darkening of Tristram (also known as Anniversary Dungeon) is a limited-time event in Diablo III that occurs in January of each year, starting with 2017. The event allows players to revisit the original 16 levels of Diablo I. It is available for both the PC and console versions, added in patch 2.4.3.

Features
The Anniversary Dungeon recreates most of the events, monsters, and levels of the original Diablo inside gameplay of Diablo III.

Returning Boss Fights are, , Arch-Bishop Lazarus and The Dark Lord (Diablo) himself. In addition, every single Unique Monster from Diablo I can be found and killed, though they are mostly just buffed-up regular monsters with no affixes (and only a few have a single affix at their disposal). They always drop Magic Items of top tier from Diablo I, for example, King's Sword of Haste, Archangel's Staff of Apocalypse or Godly Plate of the Whale (though at maximum level, these items are of little usefulness).

Monsters in Anniversary Dungeon are the same as those in D1, but use the graphical assets from D3 with only slight recolor. Some of them do have their old abilities, and some do not. Those monsters, which do not have a direct equivalent in D3, use graphics of the closest possible match (for instance, Winged Demons use graphics of Winged Talus).

The Dungeon is 16 levels deep, divided into 4 sections as the original game is (Catacombs are replaced with nephalem ruins, Caves with mines and Hell with Halls of Agony visuals). Any character can enter it: there is even an achievement and reward for beating it in one go with a level 1 character. The Dungeon also gives tremendous amounts of experience, on average, a fresh character completing it on Normal difficulty will acquire level 30 by the end of it.

All quests from D1 return, but most have been altered and simplified. For example, Poisoned Water only involves finding a Resplendent Chest in the Dark Passage. Unlike the original game, this event gives access to all of them at once. Unique quest rewards, such as Ring of Truth, are dropped in form of Magic Items with unique graphics and text, but hardly any gameplay use at maximum level.

NPCs such as Pepin, Griswold, Farnham and Ogden appear in their corpse (later ) form. Though they do not provide speech, and do not serve their direct duties, they are all involved in a semi-secret quest line (which replaces the old Black Mushroom quest).



The Dungeon is accessed via a portal in The Old Ruins of Tristram, next to the fountain, and is only accessible in Adventure Mode. The zone itself is simply named Tristram, and all 16 levels of the Dungeon are labeled Labyrinth.

Rewards
Rewards for completing the dungeon include banner elements (for killing all 4 bosses: Dark Lord, Archbishop Lazarus, and ), as well as:

Pets

 * The Butcher, modeled after Butcher: obtained for clearing Anniversary Dungeon with a fresh character in one go (must be done in single player mode).
 * Royal Calf, obtained through a semi-secret event line.

Transmogrification weapons
There are two, modeled after The Butcher's Cleaver and Wirt's Leg.


 * The Butcher's Cleaver is looted from the Butcher (it's a Magic quality item).


 * is awarded for the same event line as Royal Calf.

Portraits
Two portraits are rewarded, angelic and demonic versions of Life and Mana orbs.

Portraits require the player to kill every single Unique monster (40 in total) and to collect all Cultist Pages.

Cultist Pages

 * A timeless guardian of order gazes upon you.

Cultist Pages are tomes needed to obtain a Classic Angel portrait from The Darkening of Tristram event in Diablo III.

All 7 pages are dropped by Temporal Priests. Each waypoint zone contains exactly 1 priest, and each priest drops a single page.

See the relevant page for details.

Unique Monsters

 * You are watched by a malevolent force from years past.

Broken down by levels, the unique monster list is (in addition to 4 mandatory bosses):
 * Level 1 — None
 * Level 2 — Shadowbite,The Butcher, Rotfeast the Hungry
 * Level 3 — Madeye the Dead, Brokenhead Bangshield
 * Level 4 — Gharbad the Weak (*), Snotspill (*), Blacklash the Burning
 * Level 5 — Bloodskin Darkbow, Foulwing, Shadowcrow
 * Level 6 — Deathshade Fleshmaul, Bilefroth the Pit Master, Bloodgutter
 * Level 7 — Blighthorn Steelmace, Gorestone, Nightwing the Cold
 * Level 8 — Firewound the Grim, Zhar the Mad (*), Baron Sludge
 * Level 9 — Breakspine, Brokenstorm, Oozedrool
 * Level 10 — The Flayer, Goldblight of the Flame, Blackstorm
 * Level 11 — Bluehorn, Fangspeir
 * Level 12 — Viperflame, Viletouch, Lionskull the Bent
 * Level 13 — Warlord of Blood (*), Rustweaver, Witchmoon
 * Level 14 — Steelskull the Hunter, Graywar the Slayer, Stareye the Witch
 * Level 15 — The Vizier (*);
 * Unholy Altar — Red Vex (*), Blackjade (*);
 * Level 16 — Sir Gorash (*)

(*) These monsters will always appear, in every game.

Each level is guaranteed to contain at least one (those who are guaranteed to spawn do not prevent an additional monster from appearing), and statistically roughly 6-7 runs are required to collect all 40 of them.

Since levels 15-16 always contain all of the monsters listed, they only need to be cleared once.

Legendary Gem
Completing the Dungeon also rewards a Legendary Gem, Red Soul Shard, that fits into the Helmet slot, reminiscent of Diablo's Soulstone (into which it will transmog the helmet).

Loot
Besides other loot, that can be found within Anniversary dungeon, there is a guaranteed drop of these magic items.

Regular Magic Items

 * Archangel's Staff of Apocalypse
 * King's Sword of Haste
 * Godly Plate of the Whale

Quest Reward-Based Items

 * Ring of Truth from a Resplendent Chest in Dark Passage on Level 2
 * The Butcher's Cleaver from The Butcher on Level 2
 * The Undead Crown from Skeleton King in King Leoric's Tomb on Level 3
 * Harlequin Crest from Snotspill on Level 4
 * Arkaine's Valor after solving a puzzle on Level 5
 * Empyrean Band from Magic Rock on Level 5
 * Optic Amulet from a Resplendent Chest in the Halls of the Blind on Level 7
 * Griswold's Edge from Anvil of Fury on Level 10
 * Veil of Steel from Lachdanan's Corpse on Level 14

Visual
One of the biggest things players will notice when entering Tristram from Old Tristram is the Pixelated Rendering Effect, distorting much of the game's high details to look dated and old. For PC players, their Status HUD will be changed to look much like Diablo I did. Frame rate was also modified to be 25~30 FPS, giving it a choppy animated effect much how animations looked in the older days. Zoom does not work as well. Another large change is the player character themselves. Much like the old game, players will visually move on a hard cardinal 8 directional movement system (player models still face the 8 directions but will still have the fluid full range motions). Monsters will also use the "8 direction" rule. Players will also no longer use a running animation, sticking to a walking animation, although it does not have any effect on the actual speed of movement. Console players still have access to the Dodge Roll ability. Since Followers don't have a walking animation, they will run normally.

One of the more subtle changes are things like lighting effects being thinner and dimmer in detailing. Another is the event will ignore the setting "Display Damage Numbers", electing to not display the damage you've dealt.

Hovering over loot will display the description in Diablo's classic Exocet typeface.

Audio
Music while in New Tristram will play Tristram's original town song, while in the Labyrinth will play area specific music, depending what area you're in. While exploring the Labyrinth, gold drops will play a heavier jingle sound. Some elemental attacks have different audio cues, like the Wizard spell Spectral Blade using the Thrown Blade rune is much quieter.

Action
This event doesn't change much of the game's playable formula. What ever you've done in the normal game will carry over well into this event. Only a few small additions can be seen in the Labyrinth, like chests being trapped (upon opening, a small red bolt will come flying at the character) and nearly all barrels being explosive (though they do not harm the player).

In an unusual twist, event items obtained from this event (such as Godly Plate of the Whale, Harlequin Crest) seem to ignore the Smart Loot system, rolling unusual stats and sometimes even against your primary stat.

Achievements
There are a number of achievements that related to this event. A few are as follows (some may differ between Pc's Achievements and Console's Challenges):
 * Thank Goodness You've Returned! (Kill all 4 Bosses in The Darkening of Tristram event).
 * Adventuring Hero (Kill 1 Unique Monsters from the Labyrinth).
 * Champion the Townsfolk (Kill 20 Unique Monsters from the Labyrinth).
 * Protector of Tristram (Kill all Unique Monsters in the Labyrinth).
 * I Sense a Soul in Search of Answers (Collect all the Cultist Pages from the precursor event).
 * Pssst... Over Here... (Obtain Wirt's Leg).
 * The Dark Passage (Visit the Dark Passage).
 * The Chamber of Bone (Visit the Chamber of Bone).
 * The Halls of the Blind (Visit the Halls of the Blind).
 * An Eerie Red Glow Blurs Your Vision (Kill the Dark Lord in a solo game starting with a Level 1 in The Darkening of Tristram event).

Development
The original idea for the event began only with the intent to celebrate the anniversary of Diablo I. The idea for the dungeon began with the desire to incorporate Diablo I music into Diablo III, featuring in Adventure Mode. Its design has been described as "scope creeping" (constantly adding new content into a project). The user interface for the mode was designed by Josh Manning on his own time.

Trivia

 * The event was initially announced during BlizzCon 2016.
 * The Banner Sigil that is rewarded upon completing the achievement "Thank Goodness You've Returned!" is called "Ogden's Sign", which is a reference to the same quest name and same design on the Tavern Sign in Diablo I.