I just played trough rikus story again and it suddenly hit me, why exactly did axel unleash riku replica on zexion? Surely it wasn't because it was "more fun" to watch sora and riku as he said and I don't believe it was because zexion "failed" seeing as: 1) By what we see in KH2 the organization dosn't punish with death failing members. 2) Zexion didn't actually "fail" seeing as no one gave him orders to do what he did, he just needed riku to stop marly from taking over, which of course is a good thing for the org... SO, why?
Look at the new vids, saix is actually afraid of him I have new found respect for his character... He really is the most tragic character in the series.
