posting for the third time:Who exactly was that other Riku that appeared then?
"riku specifically distinguishes the monstro-riku as not being the replica you know...
the monstro-riku was there for the purpose of riku's redemption arc, having him literally face who he was back then.
as riku puts it, it was "his dark side""
Riku: That was my...my dark side. I gave in to the darkness once. And ever
since, it's chased me around in one form or another. The Seeker of Darkness
who stole my body...a puppet replica of the shadows in my heart...and now,
I'm facing me.