To celebrate the 30th anniversary of the Diablo franchise, Blizzard launched Diablo 4 Season 15, officially named Hell’s Legacy. Widely regarded as one of the most nostalgic seasons in Diablo 4 history, this update brings back iconic locations, classic bosses, and legendary characters from the first two Diablo games. The season officially goes live on September 15 at 9:30 AM PT. The core highlight of D4 Season 15 is the return of all three Prime Evils, along with brand-new seasonal mechanics, evil power unlock systems, unique modifiers, and exclusive rewards.
Updated on September 23, 2026:
Diablo 4 Season 15 Prime Evils Return Details & Guide
Season 15 serves as a tribute to Diablo’s classic lore and 30-year development history. The lost soul of Deckard Cain returns to Sanctuary as the key seasonal NPC. He tasks players with redeeming tormented Dark Wanderers trapped by the Prime Evils’ corruption. The most representative Dark Wanderer in the series, Aidan (the original Diablo 1 warrior and son of King Leoric), is central to the season’s storyline, reviving the classic tragic lore of the Prime Evils’ possession.
Unlike previous Diablo 4 seasons, Hell’s Legacy focuses heavily on retro gameplay experiences. It revives classic maps and boss fights from Diablo 1 and Diablo 2, letting players revisit iconic nostalgic scenes while obtaining brand-new seasonal buffs and loot.
Diablo 4 Season 15 Prime Evils Bosses & Exact Locations
The biggest feature of Season 15 is the return of the three classic Prime Evils: Diablo (Lord of Terror), Baal (Lord of Destruction), and Mephisto (Lord of Hatred). Each boss resides in their classic legacy map areas, fully restoring the classic Diablo dungeon atmosphere:
Baal: Located at the Throne of Destruction on Mount Arreat (a classic Diablo 2 map). Players need to defeat The Ancients and Baal’s minions first before challenging Baal himself.
Mephisto: Hidden deep in the Durance of Hate. Players must traverse three layers of the dungeon to reach Mephisto’s boss arena, replicating the classic Diablo 2 dungeon exploration process.
Diablo: Found beneath the Tristram Cathedral (the core classic map of Diablo 1). Before fighting Diablo, players will encounter weakened classic elites including the Butcher, Blood Raven, and the Summoner.
How to Unlock Prime Evil Powers in Diablo 4 Season 15?
Prime Evil Powers are the core seasonal abilities of Season 15, unlocked by completing Deckard Cain’s exclusive seasonal questline. The entire process is straightforward, and players can finish it after creating a new seasonal character. Detailed steps are as follows:
Step 1: Trigger the Initial Quest
After creating your seasonal character, head to Kuhuthi's Tavern to find Deck Ard Cain. Follow his instructions to teleport to the Imperial Library and start the first quest: The Horadrim’s Fate.
Step 2: Defeat Baal & Obtain the First Splinter
Progress through the Horadrim’s Fate quest to defeat Tal Rasha, The Ancients, and waves of Baal’s minions, before finally confronting Baal. New players can first level up to level 15–20 via Helltides to reduce the boss fight difficulty. After defeating Baal, you will gain experience orbs, the first Splinter of Evil, and exclusive jewelry loot like Leoric’s Crown (which can socket evil splinters).
Step 3: Defeat Mephisto & Collect the Second Splinter
Return to Deck Ard Cain to accept the second quest: The Burning Shepherd. Travel to the Hawezar zone and enter the dedicated portal. To access Mephisto’s chamber, you need to collect four classic ingredients at Travincal: Khalim’s Brain, Khalim’s Eye, Khalim’s Heart, and Khalim’s Flail.
The game will automatically combine the ingredients into Khalim’s Will. Use this item to destroy the Compelling Orb, which opens a portal to the Durance of Hate. Clear the first two dungeon layers and defeat Mephisto on the third layer to obtain runes, experience orbs, and the second Splinter of Evil.
Step 4: Defeat Diablo & Get the Third Splinter
Go back to Deck Ard Cain to unlock the third quest: The Brother’s Keeper. Teleport to Corbach and head south to find Aidan. Talking to Aidan will unlock the entrance to Tristram Cathedral.
Progress through the cathedral, catacombs, and caves to defeat the weakened Butcher, Blood Raven, and the Summoner. Continue the storyline to enter Diablo’s arena. During the fight, Diablo will gain invulnerability from surrounding Dark Portals — destroy all Dark Portals first, then defeat Diablo.
After victory, you will get the third Splinter of Evil, experience orbs, and rare unique loot such as the Stone of Jordan.
Step 5: Unlock & Equip Prime Evil Powers
Return to the Imperial Library and place all three Splinters of Evil on Deck Ard Cain’s table. Your game inventory’s Seasonal Tab will be officially unlocked. You can preview all available Prime Evil Powers and select one to equip.
A key rule: only one Prime Evil Splinter and its corresponding power can be active at a time. After equipping your chosen power, defeat enemies to level up your seasonal reputation board and unlock more upgrades.
Diablo 4 Prime Evil Splinters & Modifiers
Each Prime Evil’s Splinter provides exclusive gameplay modifiers that reshape end-game content. Every reputation track in Season 15 includes 8 activity modifiers and 6 iconic power upgrades. All three splinters also bring universal changes to the Tree of Whispers. The exclusive modifiers for each splinter are as follows:
Diablo’s Splinter of Terror: Buffs and modifies Helltide and Infernal Hordes gameplay, ideal for players who focus on Helltide leveling and farming.
Baal’s Splinter of Destruction: Adjusts the mechanics and loot rules of The Undercity and Lair Bosses, optimizing underground dungeon farming efficiency.
Mephisto’s Splinter of Hatred: Provides modifiers for The Pit and Nightmare Dungeons, suitable for high-difficulty dungeon challenge players.
It is worth noting that Prime Evil powers come with trade-offs. After equipping a Splinter of Evil, you will turn into a Dark Wanderer and gain reputation via matching activities, but you will also become more vulnerable to the corresponding Prime Evil. Random evil echoes will spawn and hunt you during gameplay, adding a continuous threat mechanic.
Diablo 4 Season 15 Best Splinter Choice
There is no universal “best” splinter in Season 15 — the optimal choice depends entirely on your preferred gameplay style, leveling route, and endgame goals. Each splinter aligns with a distinct farming and progression loop, making selection a matter of personal playstyle rather than strict meta dominance.
Baal’s Splinter of Destruction (Best for Early Leveling & Casual Farming): Widely considered the most beginner-friendly and early-game meta pick. Its Rank 4 Jade Epiphany modifier grants 50% extra Experience Orbs in The Undercity and increases monster power, turning Undercity runs into the fastest leveling method in the season. It also boosts rune drops and unique item spawns from Lair Bosses, letting new and returning players hit max level quickly while building a solid early-game build with minimal effort.
Diablo’s Splinter of Terror (Best for Helltide & Mass Combat Players): Perfect for players who enjoy open-world seasonal content and fast casual farming. Its modifiers enhance Helltide cinder farming, spawn elite demonic rats, and let Hellwyrms summon the Butcher for extra loot. It also improves Infernal Hordes rewards and shrine effects, suiting fire-based builds and players who prefer open-world grinding over repetitive dungeon runs.
Mephisto’s Splinter of Hatred (Best for Endgame Pushing & Min-Maxing): The top-tier choice for late-game players focused on high-challenge content. Its buffs to Nightmare Dungeons and The Pit drastically improve glyph upgrade odds, Artificer’s Stone gains, and rare chest spawns. While it offers fewer early-game benefits, it dominates endgame progression, making it ideal for players looking to push high Torment tiers and perfect their builds post-max level.
How to Change Prime Evil Splinter & Power in Diablo 4 Season 15?
There is no independent option to manually swap Prime Evil Powers in D4 S15. Changing your active Prime Evil Splinter is the only way to instantly switch your associated Prime Evil Power and all matching War Plan modifiers.
Core Restriction for Prime Evil Power Swapping
After completing the early seasonal questline and selecting your initial Prime Evil Power, you cannot freely swap powers on demand. Power swapping is locked by default and only unlocks after meeting specific endgame requirements. Additionally, switching your active Prime Evil Splinter will reset the progression of your currently active Prime Evil Power. Since leveling Prime Evil Powers is an extremely slow process, it is strongly recommended to fully max out your existing power before swapping to a new one.
Unlock Splinter & Power Swap Function
To enable Prime Evil Splinter (and thus Power) swapping, you must complete the high-tier Waking Nightmare capstone dungeon. This endgame unlock is mandatory for accessing any splinter swap mechanics in the Seasonal Tab.
How to Get New Prime Evil Splinters
All Prime Evil Splinter drops and related unlocks require a minimum difficulty of Torment X, with Torment XII offering the best drop rates and seasonal progression rewards. For reference, Torment X equates to Pit 80, Torment XI to Pit 90, and Torment XII to Pit 100 difficulty scaling.
1. Capstone Dungeon Echo Farming (Diablo, Mephisto, Baal)
You can farm Prime Evil Echoes in their respective exclusive capstone dungeons on Torment X+ difficulty to earn splinters:
Diablo’s Echo: Found in the Labyrinth (Scosglen)
Mephisto’s Echo: Found in the Durance of Hate (Hawezar)
Baal’s Echo: Found in the Worldstone Keep (Fractured Peaks)
While these dungeons unlock Hell difficulty at Torment X, the game officially recommends Torment XII for viable clears. Successfully completing these dungeons requires endgame-tier gear and builds—players typically need to clear Pit 115 content first, with level 100+ Glyphs and multiple Mythic items to survive the +30 level monster scaling in Torment X capstone dungeons. Note that Prime Evil Splinters are not guaranteed drops after defeating the dungeon’s Prime Evil Echo.
2. Helltide Open World Echo Farming
Prime Evil Echoes can spawn randomly in the open world during Helltide events after receiving the in-game prompt: “The Echo of a Prime Evil will soon emerge”. These echoes spawn on Torment X+ difficulty and can be farmed cooperatively with other players.
This method carries significant risks: Helltide Prime Evil Echoes have high health and deal massive damage. If all participating players die, the echo despawns permanently with no loot reward. To succeed, you must survive long enough for teammates to join, and ensure at least one player remains alive at all times during the fight.
3. Mystery Greater Archetype Caches (Fastest Farming Method)
The most efficient way to farm Prime Evil Splinters is by looting Mystery Greater Archetype Caches, exclusively obtainable on Torment X+ (optimally Torment XII) difficulty. There are two reliable sources for these caches:
Season Journey Rewards: Rank IX of the Season Journey offers numerous Mystery Greater Archetype Caches, earned by completing various Torment XII seasonal activities.
Repeatable Seasonal Board Rewards: After finishing the Season Journey, farm the Summoner enemy on Torment XII. Deplete the Summoner’s health below 33% to trigger clone spawning (scaling to Pit 125–130 difficulty). Farm up to 50,000 Evil Splinter currency by defeating clones, then claim Mystery Greater Archetype Caches from Deckard Cain’s Table (the seasonal splinter board) in Temis or the Imperial Library.
Prime Evil Power Changing Process
Once you get a new Prime Evil Splinter (stored in your consumables tab) and unlock the swap function via the capstone dungeon clear, navigate to the Seasonal Tab to swap your active splinter. Your Prime Evil Power and all associated War Plan modifiers will update instantly to match your new splinter selection.
Diablo 4 Season 15 Prime Evil Powers Full List
Every Splinter has one power and six upgrades. The power is active from rank 1, the upgrades arrive at ranks 2, 6, 10, 16, 21 and 24. Reputation comes from Waking Nightmares and slaying remnants.
Splinter of Terror Powers
Gain ranks in the Splinter of Terror by entering Waking Nightmares and slaying remnants of evils past.
Flames of Metus | Power · Rank 1 - Diablo's power erupts from you, periodically unleashing lines of Fire, dealing 20,720 damage and an additional 165,758 damage over 4 seconds.
Flaring Cinders | Upgrade · Rank 2 · 350 Reputation - Flames of Metus spawn Aberrant Cinders while in Helltide.
Pounding Heart | Upgrade · Rank 6 · 1,300 Reputation - Flames of Metus generate 50 Primary Resource.
Primeval Essence | Upgrade · Rank 10 · 5,150 Reputation - Flames of Metus spawn Aether while in Infernal Hordes.
Dread Presence | Upgrade · Rank 16 · 13,100 Reputation - Flames of Metus Slow enemies by 30% and make them Vulnerable.
Consuming Blaze | Upgrade · Rank 21 · 17,400 Reputation - When an enemy is first hit by Flames of Metus, it deals an additional 20% of their Maximum Life over 4 seconds. This damage cannot be increased.
Rapture of Fear | Upgrade · Rank 24 · 20,000 Reputation - Killing enemies can fill you with the Rapture of Fear for 5 seconds, dramatically increasing the number of Flames of Metus you unleash.
Splinter of Destruction Powers
Gain ranks in the Splinter of Destruction by entering Waking Nightmares and slaying remnants of evils past.
Ice of Excidium | Power · Rank 1 - Baal's power bursts forth from you, periodically unleashing a blast of ice, dealing 69,066 Cold damage and smaller projectiles that deal 13,813 damage.
Siege Engine | Upgrade · Rank 2 · 350 Reputation - Ice of Excidium has a chance to grant Attunement while in the Undercity.
Cold Blood | Upgrade · Rank 6 · 1,300 Reputation - Ice of Excidium generates 50 Primary Resource.
Grisly Trophies | Upgrade · Rank 10 · 5,150 Reputation - Ice of Excidium causes Bosses to have a 30% chance to drop an additional Boss Trophy when killed.
Seizing Frost | Upgrade · Rank 16 · 13,100 Reputation - Ice of Excidium Chills enemies for 10% and makes them Vulnerable for 5 seconds. Smaller projectiles Chill for half as much.
Shattered Flesh | Upgrade · Rank 21 · 17,400 Reputation - When an enemy is first hit by Ice of Excidium, it deals an additional 20% of their Maximum Life over 4 seconds. This damage cannot be increased.
Thrill of Ruin | Upgrade · Rank 24 · 20,000 Reputation - Killing enemies can fill you with the Thrill of Ruin for 5 seconds, dramatically increasing the number of Ice of Excidium blasts you unleash.
Splinter of Hatred Powers
Gain ranks in the Splinter of Hatred by entering Waking Nightmares and slaying remnants of evils past.
Ghosts of Odium | Power · Rank 1 - Mephisto's power overflows from you, periodically unleashing Ghosts of Odium, dealing 34,533 Physical damage.
Undying Rage | Upgrade · Rank 2 · 350 Reputation - While in a Nightmare Dungeon, Ghosts of Odium trigger 50% more often and deal 200% increased damage.
Flush of Bile | Upgrade · Rank 6 · 1,300 Reputation - Ghosts of Odium generate 50 Primary Resource.
Death Collector | Upgrade · Rank 10 · 5,150 Reputation - While in The Pit, enemies damaged by Ghosts of Odium have a chance to drop Progress Orbs when they die.
Strangling Grip | Upgrade · Rank 16 · 13,100 Reputation - Ghosts of Odium make enemies Vulnerable for 5 seconds and have a 15% chance to Immobilize them for 2 seconds.
Vengeful Soul | Upgrade · Rank 21 · 17,400 Reputation - When an enemy is first hit by Ghosts of Odium, it deals an additional 20% of their Maximum Life over 4 seconds. This damage cannot be increased.
Fever of Malice | Upgrade · Rank 24 · 20,000 Reputation - Killing enemies can enrage you with Fever of Malice for 5 seconds, dramatically increasing the number of Ghosts of Odium you unleash.
