This Strange Xbox Feature Lets You Use Two Controllers As One
Xbox has made a lot of strides in accessibility over the Xbox One generation, and into the Series X|S era. One such change is the ability to use two controllers as one, known as "Copilot" — not to be confused with the Windows AI assistant. Both controllers are connected to the Xbox at the same time, but they each control the same input in a game.
The idea behind two controllers serving as one input is for somebody to come in as backup if you're struggling. A scenario could be a parent helping their child get through a difficult level, without ever having to pass the controller. The parent would just use their own controller to play the game while the child watches. When the tough part is over, the parent can put their controller down, and the child can continue on at their own pace.
This feature is also somewhat-confusingly called Copilot, and it's well worth giving a try if you envision yourself ever being in a similar situation. The entire process is easy to set up, and you'll be able to turn it off whenever you like. This isn't the same as signing into two accounts, however, and only the pilot will be unlocking achievements as the copilot is just there for help.
How to turn on Copilot on Xbox
If you want to set up Copilot with your Xbox, you have to use the player one controller to do so. Press the center Xbox button, select Profile & system, go to Settings, then Accessibility, and finally, Controller. From there, you can select "Copilot settings" and toggle it on. Grab and connect the second controller, and choose it as the copilot.
Now you can use that second controller at the same time as the pilot controller. Remember, it's not the same as co-op in a game because you'll each be controlling the same things even though you're using two controllers. This feature will work with any Xbox One controller, including the Xbox Adaptive Controller.
You can do this same thing on PC by hitting the Start button, typing in "Xbox Accessories," selecting More options, and then Turn on Copilot. It works the same way as it does on Xbox, but you need to have the Xbox Accessories app installed.
If you want to turn off the Copilot feature, follow the same steps and toggle it off instead as well. You definitely don't want somebody picking up a controller and messing you up in the middle of a boss battle in "Elden Ring."