This is an archived version of the Betrayal page as it appeared during Betrayal League. The information here may not reflect later changes to Betrayal mechanics.
A League Of Our Own
(If you are playing on the permanent Standard League, you can skip this page.)
If you've followed my recommendation, your character has been created in the current league - as of this writing, Betrayal (which started in early December 2018 and should last until March 2019 or so).
This page is about the mechanics of the Betrayal League, and will update with the release of future leagues. Previous league information can be found in the Mechanics Reference under Past Leagues.
The Immortal Syndicate
Shortly after you begin playing through the campaign, you'll encounter Jun Ortoi, a friendly NPC who wants your help dismantling the hostile Immortal Syndicate.
A handful of previously-friendly NPCs - the Forsaken Masters - have joined forces with an array of characters drawn from Path of Exile's lore to form the Immortal Syndicate. The members of this syndicate do not stay dead - hence the name - and so you will fight them repeatedly as you level.
Your goal is to gain intelligence on the Syndicate, raid their Safehouses for loot, and ultimately face their Mastermind in a major endgame boss fight. On your way, you'll manipulate relationships among the Syndicate members (ever play Shadow of Mordor?) to raise or lower their ranks and shuffle them around within the Syndicate's different wings. Doing so lets you modify the difficulty - and loot - of the safehouse raids and ultimately of the Mastermind encounter itself.
Betrayal's mechanics are very complex, and you may want to just worry about killing stuff for now, then returning to this section later. Continue on for the details.
The Investigation Board
Once you've interacted with Jun Ortoi, you can bring up the Investigation Board at any time by pressing [v]. It displays the relationships among the various Syndicate members, along with their ranks and positions within the organization, as well as your progress towards raiding each Safehouse.
The Mastermind is located at the top of the screen - in this image, by a red question mark. Below the Mastermind are the four main departments of the Syndicate: from left to right, Transportation, Fortification, Research, and Intervention. Each department has its own associated missions when you encounter it in the wild, and each is led by one of the members of the Syndicate. In this image, three of the four department leaders are revealed. Each department leader's panel shows the progress towards raiding that department's Safehouse: in this case, the player is close to ready to raid Transportation, is already prepared to raid Research, and has a ways to go before raiding Fortification or Intervention.
Below the department leaders are the rank and file. Most of them are associated with a particular department - for example, Janus (far left) is associated with Transportation in this image, and Vorici (far right) is associated with Intervention. Which department a member is associated with determines the loot that they'll drop when defeated as part of a Safehouse raid. If a department head is demoted (usually by defeating them during a Safehouse raid), one of their underlings will take over the department.
Each time you defeat a member of the Syndicate, you'll be presented with a choice of two options, which will vary depending on the circumstances in which you fought them. If you fight multiple members of the Syndicate at once, these options will change, and once you make a choice for one member the other options will change depending on your choice.
The exact details of what choices are available are still being worked out by the community as of this writing (December 2018). However, it's known that the number of members you fought is a critical factor - for example, with two members present, you'll always have the option to promote one to a higher rank.
Ranks and Affiliations
Each member of the Syndicate has a rank, which can be found on their panel within the Investigation Board. They can be rank 0 (not shown), or ranks 1, 2, or 3 (displayed by a corresponding number of stars). In the image below, Riker Maloney is Rank 1.
Any member of the Syndicate above Rank 0 is associated with one of the Syndicate's departments. In this case, Riker is associated with Intervention, along with being Rank 1. A rank 0 member who becomes affiliated with a department through another member's bargaining options will become rank 1 even if not otherwise noted.
Higher-rank members of the Syndicate gain items that increase their power for each rank they gain. In this case, Riker has an item that increases his Cast Speed. These items seem to be purely negative - they don't drop from them - and can be removed through one possible option after a successful fight. Higher-rank Syndicate members drop more items during a Safehouse raid.
Which department a particular Syndicate member is associated with, on the other hand, determines the type of drops they give. Some Syndicate members may have drops you're not interested in in one department - if so, try shuffling them to another one, where they'll have different loot options. See this chart for details.
In addition to the Syndicate's own mechanics, Syndicate members can drop items with a special Veiled modifier, indicated by a line of weird scrambled text. You can speak to Jun Ortoi to "unveil" these modifiers, which gives you a list of three options to choose from.
Choosing one will apply the modifier in question to the item. Moreover, it will "level up" that Veiled modifier for the future - the more times you choose a particular Veiled modifier, the more powerful it becomes up to a limit.
Once you've unlocked a Veiled Modifier, it becomes available for crafting at the Crafting Bench in your hideout. We'll discuss Hideouts and crafting further during Act 2. Don't worry about this for now - just loot the items they drop and Unveil any that have a scrambled modifier on them.