In Proud, you clear the story and get all the stickers. In Critical, you clear the story. End of the World was a really emotional place for me because it was the heart of all the evil that had besieged the game's universe. I was emotional because I knew I was running through the remains of the Pride Lands or Beast's castle, knowing the fate my favorite childhood characters had suffered. So I'm always antsy in the Realm of Darkness, especially the areas you explore in BBS and the blueish places, that were like the area beyond the door to Kingdom Hearts. The Pureblood Heartless didn't give me any trouble until the final fight with them in the tight quarters. Dark Hide wasn't tough either, but I was about LV 55 or so. And I think he's just a random Heartless, no ties to Dark Thorn. I remember when the buildup for BBS FM was happening back in early 2011, we (on KH Insider) speculated as to what significance this Heartless would have, if he was saved for the true final boss. But yeah, he's just a nobody. Now imagine if we encountered Chernabog in the Realm of Darkness.