I am trying to defeat Xion in Mission Mode with Saix. It is extremely hard. Can someone give me some tips?
You can use Dual-wield Roxas, his air attacks is pretty good. Or you can use Riku and use the Gear that chabge his weapon to Way to the Dawn (I forgot the name of the gear ) Have a lot of healing items and healing magic. And level up as high as you can, you may also need to equip accessory that increase your critical.
If using Saix, it helps a lot if you have Critical Sun equipped, as well as Zero Gear with 3 or 4 Sight Units. This should up his crit ratio to above 50%. Auto-dodge helps save you a number of times, and Block Roll doesn't really hurt your chances (but Flame Block is arguably better in your block slot). Also, lots of Cura and Fira are essential. Maybe bring a Megalixir or two if you still don't think it's enough. Use Xion's vocal and movement cues to predict what attack she's going to do - especially in her second form, where getting hit with Ragnarok can mean instant death. To avoid that for at least some of the time, stay reasonably close to her so she isn't tempted to fire massive lasers at you. Oh yeah, and of course, block lots and roll lots.
Cura will heal u bit by bit, and it helps when the opponent constantly attacks you. This will be useful to know too
