In the console versions of Disney•Pixar Brave, a second player can jump into the action with Merida in co-op mode as a will o’ the wisp!
You will need two actively synced, paired, or connected controllers to play.
Here's how to started on each console:
Wii – During gameplay, press the + button on the second Wii remote.
PlayStation 3 – During gameplay, press the START button on the second PS3 controller.
Xbox 360 – During gameplay, press the START button on the second Xbox 360 controller.