In Diablo 4 Season 13, Undercity has become one of the most efficient endgame farming activities for players targeting Trace of Echo, Mythic uniques, Mythic Seals, and high-value D4 crafting materials.
Whether you are preparing for Torment progression, farming endgame upgrades, or chasing rare portal unlocks like the Howling Mouth of Madness, mastering this system will significantly increase your loot efficiency and reduce overall grind time.
This guide explains how the system works, what nodes matter, and how to loop Undercity runs for maximum rewards.
Undercity Loot Overview
To understand why this method works, you need to know what each run can drop.
Undercity Rewards:
● Gold: Moderate Diablo 4 gold reward per run, influenced by efficiency and tribute chest count
● Runes: Large rune drops from tribute scaling
● Mythic Items: High chance from optimized Achievement Rank runs
● Mythic Seals: Rare drops tied to high-value chest scaling
● Trace of Echo: Extremely rare drop tied to specific tribute types
● Crafting Materials: High-tier upgrade resources
● Goblin Bonus Loot: Extra tribute chests from Gutter Filth interaction
Step-by-Step Undercity Infinite Farming Method
This farming method relies on a fixed loop structure that allows you to repeatedly run Undercity while maximizing Achievement Rank, tribute chests, and rare loot triggers. The entire system is built around controlled dungeon behavior, beacon routing, and teleport reset interactions. Once this is set, proceed directly to your Nightmare Dungeon run without starting Infernal Horde.
Step 1: War Plan Setup
Before starting Undercity, open your War Plan interface and set your next activity to Infernal Horde. This setup ensures the teleport interaction later behaves consistently during the reset process and allows the loop to function without interruption.
Step 2: Select Nightmare Sigil
Use the appropriate sigil depending on your target:
● Treasure Breach Sigil is used when farming goblins, tribute chests, and general loot density.
● Mythic Prankster Sigil is used when targeting Mythic drops and focused elite farming.
The sigil must match the dungeon you intend to farm, as mismatched sigils can disrupt loot structure and reduce efficiency.
Step 3: Enter The Dungeon and Begin Target Clearing
After entering the dungeon, start by identifying your objective path:
Treasure Breach: Clear all goblins as soon as they appear while moving through spirit beacons. These enemies are the primary source of extra tribute chests and should always be prioritized over general mobs.
Mythic Prankster: Focus only on the Mythic Prankster target. Avoid unnecessary combat unless it blocks progression, as time efficiency is tied directly to loop repetition speed.
Throughout both dungeon types, spirit beacons should always be activated and checked before moving forward, since they can trigger goblins or mini-boss encounters that significantly increase reward output per run.
The dungeon boss should never be killed during this loop. Leaving it alive allows the reset interaction to remain active and is required for continuous farming.
Step 4: Beacon Routing and Attunement Control
Early in the run, every spirit beacon should be fully activated and cleared for value. Goblin spawns and mini-bosses should always be prioritized, as they directly contribute to tribute chest generation.
Once maximum attunement is reached, beacon interaction changes into a fast-scan pattern. Each beacon is activated briefly to check for goblins, and immediately skipped if none appear. Full clears are no longer necessary at this stage, as reward scaling has already been established.
This transition is where most of the time efficiency is gained in the loop.
Step 5: Reset the Dungeon Using Teleport
After finishing your target inside the dungeon, open the map and use the teleport option linked to Infernal Horde through your War Plan setup.
From here, the teleport will not always behave the same way. In some cases, it will send you toward Infernal Horde, while in other cases it will place you back inside the dungeon instance. When this happens, the dungeon effectively resets and becomes available to run again.
If the reset does not happen immediately, continue using the teleport repeatedly until the dungeon refreshes. Once you are placed back into a fresh instance, simply re-enter and start the run again from the beginning.
This is what allows the farming loop to continue without waiting for normal dungeon reset timers.
