Path of Exile: Sentinel League — the Sentinels explained in detail

Everything you need to know about Sentinels, mechanics, crafting, and more.

Image via Grinding Gear Games

In the Sentinel Challenge League, ancient robotic constructs have been unearthed across all of Wraeclast. You will have to harness the power of these Sentinels to manage your level of risk and reward on the battlefield. When deployed, they follow you around for a short while, empowering your enemies and greatly increasing their difficulty and reward.

With the latest Path of Exile League in full swing, even after a very rocky start, some players might still be wondering what this whole Sentinel business is all about. With in-game explanations vague and inconclusive at best, we have compiled an easy-to-follow guide to help you better understand and utilize our new flying buddies.

Sentinel Classes & Types

Sentinels come in three flavors called “Sentinel Classes,” each with their specific purpose once deployed. Their type determines their color (for easier distinction), their effect, and the approximate amount of shots they can fire before they’re depleted for the area. Each type of Sentinel can only be deployed once per area, at least until it is reset (either manually or due to normal expiration).

Image via Grinding Gear Games

Each Sentinel Class also comes in different types, which determine the rarity and power potential for each of them. Functionally, you can think of them in similar ways as to how the gear types progress across Item Levels.

Stalker Sentinel

This Sentinel, affectionately called “Red,” empowers a moderate number of enemies in sequence as you encounter them. It will follow you around for about thirty seconds, empowering dozens of monsters before its power fizzles out for the area.

Stalker Sentinel types in order of level:

  • Rusted Stalker Sentinel
  • Bronze Stalker Sentinel
  • Cobalt Stalker Sentinel
  • Brimstone Stalker Sentinel
  • Emberstone Stalker Sentinel
  • Obsidian Stalker Sentinel
  • Cryptic Stalker Sentinel
  • Primeval Stalker Sentinel
  • Ancient Stalker Sentinel

Pandemonium Sentinel

Affectionately known as “Blue“, this Sentinel will empower a wide swath of monsters at once in a quick, single AoE burst. They are designed for mass area-of-effect, and typically only fire one shot. But this shot really counts, chaining between monsters to affect an entire screen full of enemies at once. This type of Sentinel can be very dangerous because it empowers so many enemies at once, requiring careful planning when to deploy.

Pandemonium Sentinel types in order of level:

  • Bronze Pandemonium Sentinel
  • Cobalt Pandemonium Sentinel
  • Brimstone Pandemonium Sentinel
  • Emberstone Pandemonium Sentinel
  • Obsidian Pandemonium Sentinel
  • Cryptic Pandemonium Sentinel
  • Primeval Pandemonium Sentinel
  • Ancient Pandemonium Sentinel

Apex Sentinel

Lastly, “Yellow” Sentinels only empower rare or unique enemies; however, their effects are significantly stronger. They fire fewer shots but have a much larger impact on both the difficulty and the reward from their affected targets.

Apex Sentinel types in order of level:

  • Bronze Apex Sentinel
  • Cobalt Apex Sentinel
  • Brimstone Apex Sentinel
  • Emberstone Apex Sentinel
  • Obsidian Apex Sentinel
  • Cryptic Apex Sentinel
  • Primeval Apex Sentinel
  • Ancient Apex Sentinel
  • Cosmic Apex Sentinel
Image via Grinding Gear Games

Sentinel Mechanics & Crafting

A new Sentinel League character starts with a single slot to equip a Stalker Sentinel, but as you progress through the campaign, you can eventually unlock two more Sentinel slots for Pandemonium and Apex Sentinels, so that you can ultimately have one Sentinel of each class equipped at a time if you so choose. Each class of Sentinel can be deployed once per area that you play in, and you’ll quickly develop a feel for when each class is best used. For example, it is a good idea to deploy your Pandemonium Sentinel when you’re surrounded by a large number of monsters that you know you can handle in bulk. Similarly, using your Apex Sentinel on the map boss that you are confident of defeating can bring you even more rewards than it would normally.

It is important to note that the Sentinels cannot be damaged by monsters in combat, but they gradually deplete their internal power supply each time you use them — represented visually by a blue bar when you hover over each Sentinel equipped in your inventory. New Sentinels to replace depleted ones can be found as you play the game. However, another important note is that the Sentinels are incompatible with traditional Path of Exile crafting techniques, and using normal crafting currency on them has no effect. New Sentinels with different properties can be assembled from the depleted Sentinels that you have saved in your Sentinel cache.

Where and how to find magic or rare Sentinels

While exploring, you can find magic or rare Sentinels that have mods on them. These mods can augment their base properties, extend their duration, make them empower monsters faster, increase the number of monsters they can empower, or even the degree to which the monsters are empowered, which ultimately affects both their difficulty and rewards. Some mods will add specific drops such as currency items, essences, or unique items to monsters empowered by the Sentinels, but usually at the cost of increasing the difficulty of empowered monsters. Rare Sentinels can have more than two mods on them, and these are generally a lot more powerful than normal or magic Sentinels, especially if you are able to find the right combination of mods.

The Sentinels you find as you explore Wraeclast will become more powerful the further you progress. But some very powerful Sentinels can only come from assembling new Sentinels from depleted ones. When two of your Sentinels run out of charge, they can be combined through a Power Core to assemble a new, fully-charged Sentinel that inherits properties from both depleted Sentinels. These hybrid Sentinels may also gain special properties such as an exclusive variant base type or modifiers that can only come from the assembly process. Power Cores are one of the new special currencies for this League, which means you will have to collect some first before you can use them to combine your new Sentinels.

Image via Grinding Gear Games

This crafting method is also one of the ways of obtaining the elusive Unique Sentinels, which provide extremely strong effects when they are deployed. Their crafting is a matter of chance, and there is no surefire way to guarantee that you can get one through the use of a Power Core. The Unique Sentinels cannot be recharged once depleted, meaning that they are essentially limited-use items with powerful effects, so planning and preparation should be considered before they’re deployed.

Image via Grinding Gear Games

Sentinel Controller

While the Sentinels you find will generally get better and better as you play through the League, you can also upgrade the effects and properties of your Sentinels through your Sentinel Controller — a special interface that you can access from your Inventory.

The Sentinel Controller can be used to customize the behavior of your Sentinels by connecting “filaments” that you can arrange and rearrange on the controller to channel power to various nodes, each of which affects your Sentinels in different ways. Like the Atlas tree, these filaments may be moved around as often as you like to experiment with your preferred Sentinel playstyle.

You will initially have to power the Pandemonium and Apex Sentinel slots through the controller interface, connecting their filaments to the initial power node, and then connecting them with three filaments each. You gain power for the controller by empowering enemies with your Sentinels and then defeating said empowered foes to gain more power for new filaments.

Image via Grinding Gear Games

You can freely pre-plan your filament routes ahead of time, and then as you gain more power, it will automatically flow to the next nodes that you have connected. This way, you can strategize in advance on how to upgrade your Sentinels, and then come back to the Sentinel Controller to plan the next stage of your progression. The controller has a total of 70 filaments for you to fill out.

Recombinator Currency

Though not directly tied to the Sentinels, as you play the new League, you may find a new type of rare League-specific currency: the Recombinators. They are connected to the Sentinels through the manner in which they function. This powerful new currency lets you apply the Sentinel Assembly process to your actual items, taking any two pieces of gear from the same item class and combining them together. The results of this assembly process are unpredictable, but this could merge the best elements of each item, potentially adding an exclusive new modifier, and ultimately creating something of unprecedented power.

You can think of the Recombinators as a somewhat safer version of Vaal Orbs that lets you have some measure of control of what you may get, and with some luck, items produced through this method of crafting can allow your build to reach new heights of power.

There are three kinds of Recombinators that can drop as rare loot:

  • The Armor Recombinator
  • The Weapon Recombinator
  • The Jewellery Recombinator