Incorrect. The first (and maybe only) game to communicate between 3ds and wii u with full functionality is monster hunter 3 ultimate. Both are the same games on different systems, so they were able to connect together for group raids. I don’t think wii u could connect to 3ds online, but in the same room up to 3 3ds systems could play with a wii u system, and even better you could transfer save data between wii u and 3ds versions.
