Among the most elusive encounters in Path of Exile, Aul, the Crystal King stands out as both a lucrative and POE orbs mechanically engaging boss hidden deep within the Azurite Mine. Unlike standard encounters, Aul is not directly accessible-you must uncover a hidden path behind a Fractured Wall in the darkness. This design makes locating him less about brute force and more about understanding Delve's generation logic.

If you've ever stared at Aul's node on the map with no visible path forward, this guide will walk you through the exact methodology to find him efficiently.

Understanding the Hidden Path Mechanic

In Delve, not all paths are visible. Some routes-especially those leading to bosses like Aul-are concealed behind destructible walls located in the darkness between nodes.

To reach Aul:

You must identify the correct adjacent node

Travel into the darkness from that node

Locate and destroy a Fractured Wall using Dynamite

The challenge lies in determining which node hides the entrance.

The "Rule of Two": Your Primary Indicator

The most reliable heuristic in Delve pathfinding is the "Rule of Two."

How It Works:

Nodes in the mine are typically generated with 3 or more connections

A node showing exactly 2 visible paths is suspicious

This often indicates a missing third connection, which is your hidden path

Practical Application:

Examine all nodes surrounding Aul's location

Identify any node with only 2 connections

Prioritize this node as your likely entry point

Once you destroy the hidden wall, that node will update to show 3 connections, aligning with the mine's generation rules.

The 1-3-4 Rule: When No Clear Candidate Exists

Sometimes, no nearby node has exactly two connections. In that case, you'll need to expand your analysis.

Node Types and Likelihood:

1-Connection Nodes (Dead Ends)

Can occasionally lead to Aul

More likely if the hidden path spans a longer distance

3-Connection Nodes

Most common node type

May conceal a hidden fourth connection

Require manual checking

4-Connection Nodes

Can be safely ignored

A node cannot exceed 4 connections, so these cannot hide an additional path

Strategy:

If no 2-connection node is present, systematically test 3-connection nodes, starting with those closest to Aul.

The Empty Grid Rule: Spatial Validation

Delve operates on a grid system, and hidden paths must physically occupy space on that grid.

Key Insight:

A hidden path requires at least one empty grid square between nodes.

What to Look For:

Nodes that are not directly adjacent to Aul

A visible gap or empty tile between the candidate node and Aul's location

What to Avoid:

Nodes positioned immediately next to Aul with no space in between

These typically cannot contain a hidden path, as there's no room for the corridor

This spatial check helps you eliminate false positives before committing resources.

Locating the Fractured Wall

Once you've identified a strong candidate node, the next step is execution.

Step-by-Step:

Travel to the selected node

Move toward the darkness in the direction of Aul's node

Watch for a Fractured Wall outline (hover to highlight)

Use Dynamite to destroy it

Upon destruction:

The hidden path becomes visible

A connection to Aul is permanently revealed on your map

Efficiency Tips:

Bring sufficient Dynamite capacity upgrades

Use Flare support to safely explore darkness

Move carefully-darkness damage ramps quickly

Why Farming Aul Is Worth It

Aul isn't just a novelty encounter-he's a high-value target.

Rewards Include:

Exclusive Aul-specific unique items

High-tier crafting bases

Valuable currency drops

For Delve-focused players, consistently locating Aul can become a profitable farming strategy, especially at deeper depths.

Final Takeaway

Finding Aul, the Crystal King, is less about luck and more about pattern recognition and system knowledge. By applying the Rule of Two, validating node positions with the Empty Grid Rule, and buy POE orbs methodically testing candidates, you can dramatically reduce wasted time in the mine.

If you see a node with only two connections, start there. If not, fall back on structured elimination. Master this process, and Aul will go from a frustrating mystery to a repeatable target in your Delve runs.