The 0.5 "Return of the Ancients" update completely changes how Path of Exile 2's endgame works, and the Fortress system is basically the backbone of that new structure. Once you finish the campaign and step into the Infinite Atlas, Fortresses become your main progression path for Atlas Passive Points and the new story chain, Origins of Divinity POE 2 Orbs.

This guide breaks down how Fortresses work, what you should focus on first, and how to progress without slowing yourself down.

What the Fortress Is
In version 0.5, the Atlas is no longer just a random web of maps. Instead, it's organized around major structures called Fortresses.

A Fortress is a large, fog-covered region that blocks off parts of the Atlas. To move forward, you actually have to push into it and clear its internal layout.

Inside these zones, you'll run tower-style areas and connected maps that progress the Origins of Divinity storyline. This is also where a big portion of your Atlas Passive Points come from, which makes Fortresses a core part of endgame power scaling-not optional content.

Why Fortresses Matter
There are two big reasons most players focus on Fortresses early:

First, they are one of the main sources of Atlas Passive Points in 0.5. With the Atlas tree now going well past 200 points, ignoring Fortresses means leaving a huge amount of power on the table.

Second, Fortress progression unlocks deeper systems, including repeatable encounters with the Arbiter of Divinity and faster access to higher-tier maps once your build is ready.

Because of that, many players choose to "live inside" Fortress progression until they reach around T15 maps and have roughly 50–100 Atlas points. It keeps progression focused instead of scattered across weaker content.

Getting Started After the Campaign
Once you finish the campaign and enter the Atlas, you'll start using Waystones to access maps. Early on, your goal is simple:

Clear your first tower and unlock the Fortress chain.

This step kicks off the Origins of Divinity storyline and activates Fortress zones on the Atlas.

At this stage, it's best not to jump into every system at once. Focus on learning Fortress layouts, understanding how dangerous fog zones are, and figuring out what map modifiers your build can safely handle.

How Fortress Progression Works
Fortresses feel like a mix of story dungeon and high-tier map content. As you move through them, you'll usually:
Push through fogged-off sections of the Atlas
Clear tower areas connected by corridors and halls
Work toward boss encounters like the Arbiter of Divinity

Along the way, you'll also find hidden progression points tied to Patriarch and Matriarch citadels, often marked by visual cues in the fog. These are important for unlocking more Atlas progress.

The Arbiter fights are especially important, since repeating them gives large chunks of Atlas Passive Points and accelerates your overall progression.

Core Strategy: Don't Rush Out Too Early
A common approach in 0.5 is to stay focused on Fortress progression until your build is fully stable.

In practice, that means:
Push Fortress maps as high as your build can comfortably handle
Aim to reach around T15 maps before branching out
Build up roughly 50–100 Atlas Passive Points first

You can always step out for variety, but Fortress is designed to be your main power-building phase early in endgame.

Atlas Passive Tree Focus
The Atlas tree in 0.5 is much larger, so early choices matter a lot.

Good early priorities include:
Map sustain and Waystone efficiency nodes
Generic defensive and reward boosts for tougher maps
Quality-of-life upgrades like extra tablet slots or improved drops

The goal isn't to specialize too early. It's to make Fortress runs smoother and more consistent so you don't stall out.

When to Move Beyond Fortresses
Once you're comfortably farming higher-tier maps and have a solid base of Atlas points, you can start branching out.

At that point you can:
Explore reworked mechanics like Breach, Delirium, Ritual, or Expedition
Or continue pushing Arbiter of Divinity for even more Atlas power

Both routes are valid-Fortress just gets you to the point where those systems feel playable and rewarding instead of overwhelming.

Builds That Work Well in Fortresses
Fortress layouts tend to be tight and punishing, so certain build traits stand out:
Strong area clear in narrow spaces
Reliable defenses for chained fights
Simple gearing progression that comes online early

Tankier melee builds or minion-based setups tend to feel very smooth here, especially for league start progression or Solo Self-Found play.

Practical Tips
A few small habits make Fortress grinding much easier:
Pick maps that match your build's strengths
Avoid dangerous modifier combinations that can brick runs
Prioritize survivability early-damage comes later
Watch for fog indicators that lead to hidden citadels and bosses

These small adjustments add up quickly over dozens of runs.

Why the Fortress System Works
The Fortress system gives 0.5's endgame a much clearer structure. Instead of randomly jumping between mechanics, you have a defined progression path: push Fortresses, grow your Atlas power, complete the Divinity storyline, then branch out into deeper systems.

It creates a smoother sense of progression where your character gradually "comes online" instead of hitting a wall.

Once you break out of Fortress progression with a strong Atlas and a stable build, the rest of the endgame opens up into a much wider mix of bosses, mechanics, and farming strategies Divine Orb.