Anomaly

Ability

Each night, you must choose a player (not yourself): you join their opposing team. You do not know which team you are on.

John is on the Loyalist team. The Anomaly wakes up and chooses John. The Anomaly joins the Subversive team because John was on the Loyalist team.
Jane is on the Subversive team. The Anomaly wakes up and chooses Jane. The Anomaly joins the Loyalist team because Jane was on the Subversive team.
The Anomaly is malfunctioning. John is on the Loyalist team. The Anomaly wakes up and chooses John. The Anomaly does not change team because the Anomaly is malfunctioning.

In a typical game most players are on the Loyalist team, so you can be fairly confident that you chose a Loyalist player and thus have joined the Subversive team.
Whilst your existence in a game will usually be harmful for the Loyalist team, it is possible that with the help of a Loyalist player who could check your team, you could discover which players are on the Subversive team and help the Loyalists to win.
You’re likely to be on the Loyalist team, but you should consider keeping your options open! It’s hard to know for certain which team you are on, and the last thing you want is to the lose the game for your own team unknowingly!

Each night, wake up the Anomaly. Tell them to choose a player. Change the Anomaly’s team to the opposite team of the player they chose. Send them back to sleep.
The team that the Anomaly starts on, before they choose a player on their first night, is up to your discretion.