So, I was looking at TV Tropes again and found that in the original Chain of Memories, "That one boss" is different than what I thought. I actually thought it was Vexen. It certainly IS/was to me, but it turns out that it's:
Captain Hook(I didn't have much of a problem with this one, but in the GBA version, it looks like he was much harder). Honestly, though, EVERY boss so far in Re:COM is that one boss, except Larxene and Axel.
Riku Replica. No surprise there. He's said to be even harder in Riku's story.
No wonder I've been stalling for so long. Playing through other games doesn't help any. Lol!
"Now, Sora! NaminÃ©! Riku! Marluxia! Larxene! It's about time you gave me one hell of a show!"
Eh, not right now. *snerk*