Bhk probally shouldn't exist because original keyblade masters are light or dark, not twilight(not saying that a twilight keyblade exist because bhk wouldn't be wielding oblivion and oathkeeper), AND LIL_RIKU YOU NOOBY IDOT SHELLS DON'T HAVE HEARTS AND YOU NEED A HEART TO WIELD A KEYBLADE. the other side of sora heart refers to the connection that sora has with bhk because he is a KEYBLADE MASTER( NOT COUSIN, BOTHER, TWILIGHT SORA, DARK SORA, or for the love of god LIGHT SORA , plz i will flame for now on ANY alternate reality post). That is how sora is connected to bhk since all keyblade masters are connected that way. they share memories, like in COM, with sora being able to go to twilight town even though he never been there before, or mickey finding Riku even in the TOTAL DARKNESS( ok they maybe some light but the last time I checked mickey couldn't escape the dark world), also all the worlds that riku can go to even though he never been there. That is because sora and riku share that keyblade master connection too.