Ok so on the DDD banner we see a hidden mickey, keyblade emblem, heartless, kh, sora crown and then 2 other symbols that look similar. They are both reminiscent of the heartless/nobody/unversed/master emblems. So here just discuss what you think they are.
1. Probably the most common and basic theory: These two symbols will be Sora and Riku's master emblems.
-why? They are two seperate symbols but they look the same.
When I come up with more I'll post or I'll post yours up here