The game allows you to add new characters and even make your mod to Friday’s Night Funkin. To do this, draw your character and add it to the sprite sheet. On this .png file will be your own character with all poses that he/she will take during the music battle against Boyfriend.
Also, you need a .xml file to define all frames for Boyfriend’s opponent. On the Internet, there are several different ways presented, exactly how to add a new character or simply replace the existing one, so it will be necessary to simply follow the instructions that it is necessary to replace in the game code and which folders need to add a character.