originally posted by SpinkByUs
That is most certainly not the plot of Kingdom Hearts 3. First of all, it's already been confirmed that the three "chasers" in the secret video are not Sora, Riku, and Kairi.
If you've seen the entire video, you'll see all three chasers without their helmets. The Roxas look-alike is Ven, the girl chaser is Aqua, and the tallest brown-haired one is named Terra.
In theory, these characters are from the past, and are most likely the souls of the original keyblade wielders, or the ancestors of Sora, Riku, and Kairi.
As you can see, none of their keyblades are real, so they're not the true forms of the keyblade wielders.
The identity of the old man is unknown, but it seems as though he was once a chaser; the one who gave into the dark and never came back, and is somehow realated to Ansem/Xehanort.