Originally Posted by Skyblade
I am going to spoiler my reply, since it involves KHII bosses. I'd suggest putting spoilers on the thread title too.
(SPOILER)Ok, on both of these, Cure and Reaction abilities are your best friends. Unlike most Reaction abilities, you can use "Learn" multiple times to collect multiple instances of the "Jump" ability. Each time Xaldin uses his spears to attack you, rapidly press the Triangle button. Since he usually attacks several at a time, you can collect a vast number of Jumps. While using your Jumps, you can inflict damage and it is difficult (if not impossible) for him to hurt you while you're Jumping. Also, don't forget about your forms. Use whichever is the highest level, since the larger your Form gauge, the longer you can stay in the form. Even Anti-Form is useful, since you get a large speed boost from it.
As for the Grim Reaper, the key is to catch him with the Reaction ability "Hinder" when he goes to use the suction vortex on the coins, and to follow it up with the "Booty Buster", which flings the weapon you stole from the Grim Reaper (you steal it when you use "Hinder"), and flings it back at the Grim Reaper, knocking out around 300 Coins. Also, if you have the Draw ability, you can use it to get the Coins from further away. You can equip the Keyblade you got from Captain Jack last time you were here to boost the effect. Other than that, just heal and beat the crud out of him when he's low on coins.