Sanctuary field notes

Diablo IV Field Guide

Researched, versioned notes on Diablo IV systems and decisions.

War Plans in Season 15: choose a Splinter, build seven activity trees

Scope: Season of Hell’s Legacy, live 3.2.1 rules
Checked: September 27, 2026
Status: Working guide. The Prime Evil pairings and shared progression are official; individual seasonal node descriptions and the allocation advice below are based on current community tooltip transcriptions and need an in-game check.

The short answer

For leveling and early Paragon, start with Baal’s Splinter of Destruction and Kurast Undercity. Put your first Undercity activity point into Jade Epiphany, which awards Experience Orbs as you raise Attunement. At Baal reputation rank 4, its seasonal line grants 50% more Experience Orbs in exchange for +1 more Monster Power. Fast runs that reach Attunement ranks are a substantial XP engine; one player reported unusually fast leveling with this route. Add Finely Tuned → Pathfinder as points arrive if you consistently reach maximum Attunement. Run overlapping Whispers for another source of progress. Jade Epiphany’s Season 15 tooltip transcription; Undercity leveling explanation.

Move to Mephisto when Glyph levels, Escalation sigils, targeted Soul Splinters, or Artificer’s Stones become the bottleneck: build Nightmare Dungeons toward Recurring Nightmare → Branching Pathways and the Pit around Choron’s Haste and Blessing. Baal remains useful for Lair Boss Uniques and Runes. Choose Diablo when your session is mostly Helltide and Hordes, especially if you want cinders, boss keys, Talismans, or Bartuc. These are recommendations by farming goal, not a claim that the combat power of one Prime Evil is universally strongest. Blizzard’s Season 15 activity pairings; Kay’s activity comparison at Mobalytics.

How the two layers fit together

After the Lord of Hatred campaign, use the Command Table in Temis to assemble a chain of activities and rewards. The table generates a key if needed, you can teleport between completed steps, and finishing the plan awards its War Chest. The six selectable activities are Nightmare Dungeons, Helltides, Undercity, Lair Bosses, Hordes, and the Pit. Whispers are a seventh activity tree, but Whispers are not selectable plan steps: they can overlap an activity and earn their own progress. Each activity earns points for its own tree; these are seven separate allocations, not one pool to divide among seven trees. Blizzard’s War Plans introduction; Kay’s seven-tree overview.

Season 15 adds a second layer. Your Splinter of Evil (Diablo, Baal, or Mephisto) has its own reputation ranks and an Iconic combat power. At specified ranks it adds seasonal effects to named nodes in the matching activity trees. You still plan around the actual node in your activity tree: the Splinter does not give you seven extra activity points. The seasonal rank is out of 24; an activity tree has up to seven points. Check the green seasonal line on the node tooltip and ensure the node is allocated and the correct Splinter is active. Blizzard’s seasonal system; eRnstl’s transcription of the 24 node bonuses.

The command-table level, activity-tree points, Splinter reputation, Season Rank, and character/Paragon levels are separate progress. In Season 15 earned War Plans points and reputation are shared between characters only when Seasonal/Eternal, Hardcore status, and Solo Self Found status all match. Each character makes its own allocation. Blizzard’s account-sharing rules.

Which Prime Evil actually changes your War Plans?

Bear this Splinter Combat and activity effect Seasonal tree bonuses worth noticing Main cost / fit
Diablo: Terror Periodic Fire lines. Its power gains cinder generation in Helltide at Splinter rank 2 and Aether generation in Hordes at rank 10. Helltide: elite rats for cinders (rank 4), Hellwyrms may bring the Butcher (12), longer, faster shrines (18). Hordes: a Doomsayer each wave (5), an earlier Impending Doom trigger (14), Chest of Talismans costs 1 Aether (20). Whispers: more Corrupted Roots (8), with extra cinders when planted in Helltide (22). Best for a Helltide/Hordes loop. The Hordes reward is late and the activity takes time; do not assume a six-wave plan run is a reliable 666-Aether Bartuc farm.
Baal: Destruction Periodic Cold blast. Its power can add Undercity Attunement at rank 2 and gives bosses a 30% chance of an extra Boss Trophy at rank 10, according to the current seasonal tooltip transcription. Jade Epiphany awards Experience Orbs on Attunement increases; Baal rank 4 gives 50% more while adding +1 Monster Power. Undercity also gains an invasion portal each floor (8) and a wider Last Gasp window (12). Lair Bosses: extra Runes (14), more Nemesis portals (18), three additional cross-class Uniques per Hoard Chest (20). Whispers: more ambushes (5), stronger boss ambushes with Superior Lair Keys (22). Recommended for leveling and early Paragon through fast Undercity runs, then keyed boss farming. Extra Monster Power and invasions can slow an unfinished build; Hoard loot still requires keys.
Mephisto: Hatred Periodic Physical ghosts. In Nightmare Dungeons they trigger 50% more often and deal 200% increased damage at rank 2; in the Pit damaged enemies can drop Progress Orbs on death at rank 10. Nightmare Dungeons: 50% chance of a second War’s Bounty Chest (rank 4), more boss revivals and +1 Monster Power (8), elite kills may reveal Horadric Altars (12). Pit: 50% more Artificer’s Stones (14), extra Glyph chance per five minutes left (18), Glyph success chance as if ten tiers higher (20). Whispers: XP orbs (5), two Sparks instead of one if a Spark procs (22). Best for Escalation inputs and Glyph progression. The Whisper Spark effect improves the payout conditional on a Spark drop; it does not guarantee one. A slower Pit can erase the value of speed-based bonuses.

Blizzard confirms the pairings, damage types, vulnerability to the associated Prime Evil, and eight activity modifiers plus six power upgrades per track. The individual ranks and amounts above come from Helltides’ power transcription and eRnstl’s node transcription, independently cross-checked against Icy Veins’ list. Tooltips can differ after hotfixes; inspect the active node before committing a specialized path. The three Prime Evil Splinters are not the eight socketable jewelry Soul Splinters; see the Season 15 guide.

Progress each activity tree toward a payoff

The arrows show priority targets, not a claim that every arrow is a direct edge in the planner. Follow the visible prerequisites in game. Earn points in the activity you actually run; start with its first useful branch and finish a payoff before investing time in another farm. Aiden Nguyen’s starter and seven-point allocations and Kay’s path comparisons informed the choices below.

Tree First points → later payoff Alternative and tradeoff Recommended use
Nightmare Dungeons Work toward Dread Revival → Recurring Nightmare → Branching Pathways. Recurring Nightmare enables Escalation sigils; Branching Pathways adds choices between floors, useful for selecting a matching Gem Reserve and farming a named jewelry Soul Splinter. Waking Spoils and the loot side add completion chests. Gauntlet/Nemesis add shrine or elite encounters; Fearless Conviction rewards clean combat. The extra enemies and revived boss cost time or safety. First priority in a Mephisto loop if you need Escalations, crafting materials, or a targeted Splinter. Add loot nodes once you can clear efficiently.
The Pit Start with Choron’s Haste → Heart of Stone → Choron’s Blessing for additional Glyph chances. Add Choron’s Wager when Artificer’s Stones are the bottleneck; Hatred enhances it at rank 14. Damned Thieves adds rewards; the Pit Butcher route has a sharp fail condition if he kills a player. Speed, survival, and tier determine whether extra chances pay off. Run a tier you finish quickly and safely. Prioritize Glyph nodes until your target Glyphs are leveled; then move points toward Stones or speed.
Tree of Whispers Invest in Wisdom of Whispers for XP and work toward Resplendent Favor for a chance of a Spark from a cache. Complete Whispers alongside your other activities. Grim Retribution → Colossal Foe and the ambush side feed boss keys, especially with Baal. Corrupted Roots → Roots of Power suits Diablo/Helltide. Ambushes add danger and completion time. Keep Whispers active regardless of Splinter; choose XP/Spark for a general route, boss keys with Baal, or roots/cinders with Diablo.
Helltide Hellmouth → Writhe and Rot builds the Hellwyrm/maggot loop; Wretched Vermin improves cinder density, particularly with Terror rank 4. Extend into Tainted Shrines as you gain points. Left-side Mindcage/difficulty upgrades increase rewards and risk. The cinder protection/efficiency side is safer; a 666-cinder chest is a deliberate spend. Meat Brothers adds harder Butcher encounters. Favor the maggot and rat route when you need XP, cinders, Forgotten Souls, and boss keys. Dial down difficulty if the added enemies stall your clear.
Kurast Undercity Put the first point into Jade Epiphany to generate XP orbs when Attunement rises. At Baal rank 4 it gives 50% more Experience Orbs, with +1 more Monster Power. Then pursue Finely Tuned → Pathfinder for a faster finish after maximum Attunement. The Gutter Filth → Trials and Tributes branch pursues Pranksters and extra Tribute Chests, which require Tributes to open. Initiative rewards a fast boss kill; other paths add materials or Ancestral Armament Tributes. Extra Monster Power and chasing side rooms can break the timer. First tree to prioritize for leveling if you can clear quickly and raise Attunement. Change to Tributes or targeted loot once you have the levels you need and consistently beat the clock.
Lair Bosses Start with Two by Two for Nemesis opportunities, then take Lair of Runes/Lair of Plenty when direct boss loot is the goal. Baal enhances Runes at rank 14 and Nemesis portals at 18. Grigoire’s Gambit, Out of the Cold, Dog of Astaroth bring bosses or their loot into other activities. A deeper middle route chains bosses and Hoards, but requires damage, survival, and keys; Golden Hoard trades salvageable non-Unique gear for Gold. Choose cross-activity nodes if you are still gearing through Helltides/dungeons. Move into Hoards when you have a boss target and keys to open the chests.
Infernal Hordes Method and Madness → Total Chaos emphasizes Chaos Waves, then consider Council Coffers for Talismans. Diablo’s late Terror rank 20 reduces that chest to 1 Aether. Reign in Hell → Pulse of Aether favors controlled Offerings and Aether instead of Chaos Waves; the other side makes the run harder for more guaranteed Aether. Chaos and Offering-control paths pull in different directions. Take Hordes for Bartuc, Talismans, or a specific loot goal, not merely to finish a plan quickly. For a 666-Aether Bartuc attempt, use a ten-wave compass and the map entrance; see the Bartuc guide.

A seven-point tree is a budget, not a mandate to take one entire side. Several high-value setups mix branches. The table states target effects and tradeoffs; use the in-game tree connections to reach them, and compare current tooltip numbers before spending. In particular, the precise edge/prerequisite ordering of every seven-point setup and whether an unallocated node’s seasonal line can ever apply have not been tested here.

A practical progression route

  1. Unlock the table and finish the seasonal quest. The first gives you activity chains; the second gives you the three Prime Evil choices. Select the Splinter that matches the next activities you will actually farm. A Splinter switch requires another consumable from the large Waking Nightmares, so check its availability before planning a rapid sequence of swaps. Blizzard’s unlock and switching descriptions; Season 15 rules.
  2. Level with Baal + Undercity + overlapping Whispers. Take Jade Epiphany with the first Undercity point and get Baal to reputation rank 4 for the extra Experience Orbs. Raise Attunement promptly, collect the orbs, and repeat at a difficulty you clear comfortably; do not add Monster Power or side events that slow the run so much that XP per minute falls. As points accrue, add Finely Tuned and Pathfinder. Season 15 also increased War Plans XP rewards, especially at higher Torment, making completed plans more rewarding. Blizzard’s 3.2.1 War Plans changes; Jade Epiphany’s seasonal bonus.
  3. Move to Mephisto + Nightmare Dungeons/Pit when Glyphs and upgrades become the bottleneck. Get the Escalation path and core Glyph nodes; choose plan rewards you need, such as keys, reagents or Stones. Keep Baal if your next goal is Undercity XP or Lair Boss Uniques and Runes. Baal’s rank-20 Exotic Armory bonus is powerful but a later reward, so it need not dictate the first leveling route.
  4. If cinders, keys, Talismans, or Bartuc are the bottleneck, shift to Diablo + Helltide/Hordes. Use Helltide for steady farming. A War Plan-generated Horde can be shorter than a ten-wave compass run, so confirm the wave counter before treating it as a Bartuc attempt.
  5. Reallocate for the next bottleneck. If extra Monster Power, bosses, or side events reduce completions per hour, take the safer branch. Claim the War Chest after completing the plan. Keep an eye on a Whispers objective that overlaps the route.

Still to verify in game: exact prerequisites for each proposed mixed branch; the current tooltip and cost of reallocating; whether a separately launched compass run credits a Hordes plan step; whether reputation already earned on an inactive Prime Evil remains when switching back; and how each power’s real damage compares on a specific build. These do not change the official activity pairing, but they matter before optimizing a character’s final seven points.