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Diablo IV Season 15: Season of Hell's Legacy Guide

Start Season 15 by choosing a Splinter of Evil, running its associated activities, and advancing War Plans. This overview also separates Waking Nightmares from the equippable Soul Splinter system.

Verified patch: 3.2.1Started: 2026-09-15Verified: 2026-09-22Weekly review
QUICK ANSWER

Finish the Seasonal Questline, activate one Splinter of Evil, and run its associated activities together with Whispers. Treat Soul Splinters as a separate Jewelry system.

START

First Steps

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STEP 01

Enter the Seasonal Realm

Create a Seasonal character or use Rebirth. Before Rebirth, unequip gear and empty the inventory so nothing important is left behind in the transfer to the Eternal Realm.

STEP 02

Defeat the Three Prime Evils

Follow the Seasonal Questline through Diablo beneath Tristram Cathedral, Baal at Arreat Summit, and Mephisto in the Durance of Hate to collect all three Splinters of Evil.

STEP 03

Choose One Splinter of Evil

Only one Splinter of Evil can be active. Choose Terror, Destruction, or Hatred according to the activities you want to run.

STEP 04

Stack Activities with Whispers

Prioritize the activities tied to the active Splinter and overlap them with Whispers. Use the resulting progress to unlock War Plan modifiers and upgrades.

LOOP

Season 15 Core Loop

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STEP 01

1. Activate a Splinter of Evil

Activate Terror, Destruction, or Hatred to match the content you plan to run next.

STEP 02

2. Run Its Activities

Terror covers Helltides and Infernal Hordes; Destruction covers Kurast Undercity and Lair Bosses; Hatred covers the Pit and Nightmare Dungeons. Whispers contribute to every Splinter.

STEP 03

3. Upgrade Through War Plans

Use progress from the associated activities to unlock modifiers and upgrades for the selected Splinter through War Plans.

STEP 04

4. Improve Waking Nightmare and Soul Splinter Runs

Clear Waking Nightmares and collect Soul Splinters for Jewelry. The Horadric Cube can combine Soul Splinters of the same type and rarity into the next rarity.

SPLINTERS-OF-EVIL

Choose a Splinter of Evil by Activity

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Splinters of Evil drive seasonal progression. They are separate from Soul Splinters equipped in Jewelry.

Splinter of Terror: Diablo

Choose this for Helltides and Infernal Hordes.

Splinter of Destruction: Baal

Choose this for Kurast Undercity and Lair Bosses.

Splinter of Hatred: Mephisto

Choose this for the Pit and Nightmare Dungeons.

WAKING-NIGHTMARES

Three Forms of Waking Nightmares

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Each form has a different scale and location, so do not expect a single shared entrance pattern.

Large, Fixed-Difficulty Version

A multi-floor, fixed-difficulty capstone version. Its highest tier is presented as a Torment 10+ challenge.

Fixed Dungeon Version

A standard dungeon-style form with a fixed location in the world.

Open-World Version

A short, one-room encounter that appears in the open world and recalls bosses or enemy groups from earlier Diablo games.

SOUL-SPLINTERS

Soul Splinters Are Special Jewelry Gems

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Each Soul Splinter grants a strong benefit and a liability, so review both sides before equipping it.

Equip Up to Three

You can equip up to three Soul Splinters across available Jewelry slots.

Four Rarity Tiers

They drop as Magic, Rare, Legendary, or Unique. Amalgamation in the Cube upgrades matching type and rarity into the next tier.

Eight Soul Splinters

The eight types are Anguish, Sin, Lies, the Black Soulstone, Pain, the Mother, Hellfire, and Damnation. Exact effects will be covered after in-game verification.

PERMANENT-UPDATES

Permanent Updates to Review This Season

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Separate seasonal mechanics from changes that also affect the Eternal Realm.

Shared War Plan Progress

War Plan progress is shared when Realm, Normal/Hardcore, and standard/Solo Self-Found categories all match.

Direct Mythic Crafting

Direct Cube crafts receive a Crafted tag, and only one directly crafted Mythic can be equipped. Track these separately from Mythics acquired through other methods.

Upgrade to Mythic

Upgrade to Mythic is described as preserving the source item's affixes and applied modifications. Do not reuse Season 14 material costs for this season.

PATCH 3.2.1

Patch 3.2.1 Checks

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  1. Season 15 adds Splinters of Evil, Waking Nightmares, and Soul Splinters.
  2. Fixes affect the Splinters of Lies, Pain, and the Mother.
  3. Echo of Mephisto has improved loot quality and a guaranteed Mythic drop.
  4. Expert and Penitent now unlock after the Prologue rather than full campaign completion.
CAUTION

Easy Mistakes to Avoid

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  • Splinters of Evil select a progression path; Soul Splinters are special gems equipped in Jewelry.
  • Only one Splinter of Evil can be active at a time.
  • Every Soul Splinter pairs its benefit with a liability.
  • Do not carry Season 14 costs, farming routes, or build rankings into Season 15 without re-verification.
NEXT

Related Guides

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War Plans Guide

Review shared progress and endgame activity routing.

Horadric Cube Guide

Review amalgamation, upgrades, and crafting basics.

Lair Boss Guide

Review the boss loop associated with the Splinter of Destruction.

Diablo IV Reference Guide

Return to progression, equipment, and activity guides.

SOURCES

Official Sources

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Blizzard: Season of Hell's Legacy Overview and 3.2.1 Patch Notes2026-09-22Blizzard: Season of Hell's Legacy Overview2026-09-22