In the Path of Exile: Mirage (Patch 3.28), Nightmare Maps are a major endgame overhaul that effectively replace the current Tier 17 maps.
Tier 17 Maps Changes 3.28
Tier 17 Maps have recieved significant changes to better align with their original design. These are now called Nightmare Maps and are now tier 16, with their primary purpose being to obtain Uber Boss Fragments.
Endgame Changes 3.28
Certain locations will require special map items to access, such as Unique Maps, Shaper Guardian Maps, Nightmare Maps, Vaal Temple and locations requiring Map Fragments rather than Map Items.
Tier 17 Maps have undergone significant changes, and are now Nightmare Maps.
Atlas Progression: Completing each Nightmare Map now awards 1 Atlas Skill Points (5 total).
Slightly increased the reward values of Originator-influenced and Nightmare Map modifiers that granted Increased Pack Size or Item Rarity.
Slightly reduced the reward values of Originator-influenced and Nightmare Map modifiers that granted More Currency, Maps or Scarabs.
Added 5 new Map Modifiers that can roll on Originator-influenced and Nightmare Maps.
List of Specific Nightmare Map Names
Known Nightmare Maps (formerly T17s) include:
Abomination Map
Citadel Map
Fortress Map
Sanctuary Map
Ziggurat Map
Key Changes and Purpose
Replacement for T17s: They are designed to solve the "T17 problem" where specific maps were forced as both the best pinnacle farm and the only access to Uber bosses.
Uber Boss Access: These maps still contain the bosses required to access Uber Pinnacle content.
Adjusted Difficulty: Nightmare Maps feature a reworked and significantly less "frustrating" pool of modifiers compared to the old Tier 17s.
Atlas Positioning: They are located on the outer corners of the Atlas, meaning they are not affected by the new Egan system, allowing other maps to be the primary focus for layered "juicing".
Bestiary
The Beastcrafting recipe for gaining Five Kirac Missions instead now grants a Nightmare Map.
Example: Graven Trail Nightmare Map
Monster Level: 83 Item Quantity: +81% Item Rarity: +94% Monster Pack Size: +30% More Maps: +35% More Scarabs: +36% More Currency: +47%
93% more Monster Life
Monsters have 700% increased Critical Strike Chance
+74% to Monster Critical Strike Multiplier
Monsters have a 50% chance to avoid Poison, Impale, and Bleeding
Monsters have +100% chance to Suppress Spell Damage
Players have 40% less Cooldown Recovery Rate
Area contains patches of moving Marked Ground, inflicting random Marks
Travel to a Map by using this in a personal Map Device. Maps can only be used once.
Note on Acton's Nightmare
Don't confuse these new endgame maps with Acton's Nightmare, which is an older, unique Overgrown Shrine map. It is famous for its Restless Dead modifier, where monsters and the two bosses (Rose and Thorn) resurrect after 10 seconds unless their corpses are destroyed.
