It isn't Japanese. Ethers and elixirs would be needed because you will usually want to use aero while fighting Riku. His attacks are very painful unless you have aero equipped.
*sees below message* I have platinum already. :3 It seems that ars arcanum doesn't help too well. But I found out that using aero helps a lot, because takes out half of the damage the attack usually does. So mainly, I need to bring in a lot of potions and ethers/elixirs.