I just remembered this yesterday, the theory suggested to us by @kimicatdemon from last year.
I'm pretty sure this is where the MAPLE theory originated too.
The theory suggested that each of the Heroes had a specific theme. Mercedes was heart, Evan was Soul and Aran was Body (as far as i can remember!) which was further reinforced by Evan's logo and the symbol on Mercedes arrow in the artwork.
Since then Phantom and Luminous have been revealed. So do you think the theory still stands?
Is Phantom the Mind hero?
and what would Luminous be? Balance?