2P Hetalia has started after Hima let out secondary designs for Nyotalia and the main Axis. Usually 2P is the “other” outfit a character could receive during a video game. Although there were no specifics given to them with personality or anything else, they have been instead been taken to be seen as “opposites” of their main counter parts. They are generally twisted and more dark than the originals. 

Since there is no official description though, its essentially another time when everything is left up to the fandom to decide! Each 2P can be played differently without there being much to despite since nothing has been decided besides some outfits.