I'm here to revive this although Outcast ended...I still have so many questions about the ending. Tae mentioned that all of Bangtan were once trapped a house with in deadly (?) circumstances as part of a "game." Yoongi apparently saved everyone and himself, sans Taehyung and Seokjin. From what the end says, Taehyung took over the game and changed some aspects of it, then asked Jin to forge five stars recommend it to the rest of Bangtan. I think I got some of the points wrong (it's been a while since I've read it), but yeah.
Everyone's pointing out details and creating such deep theories...and then there's me