Mission 93: Believe
Mission 93 in Kingdom Hearts 358/2 Days is the last mission in Roxas's storyline. On a quest to free Kingdom Hearts and reclaim Xion, Roxas is interrupted by Riku, who seeks the Keyblade wielder for his own accord. The dark enigma wishes for Sora's Nobody to come quietly, but Roxas has other plans.
Roxas must evade the Neoshadows that Organization XIII sent to retrieve him. The renegade then battles Riku, as the dark warrior stands in his way on his quest to free Kingdom Hearts and to reclaim Xion.
This is the only mission in Story Mode in which Roxas can Dual-Wield. Being able to cut through Neoshadows like butter, the first group of Heartless should be no problem to destroy. Defeat the occasional duos of Purebloods that pop up for extra experience, but otherwise evade them and head to Memory's Skyscraper. Make sure to grab the Mission Badge and Blazon, which are both located in the industrial area after the second group of Neoshadows and before the third group. One is directly up the wall to your right as you enter the gate, the other is just above the platform to your left. Battle the scripted last batch of Neoshadows and prepare for the final battle of the game.
Once the battle with Riku starts, Roxas loses his Dual-Wield ability because Riku is using the Oblivion, leaving you with the Oathkeeper. Quickly run up to Memory's Skyscraper to obtain the Unity Badge. Utilizing the Glide ability, dodge Riku's fast strikes while getting in for a quick combo. Riku can easily be taken down with Event Horizon, as well as careful timing of the Block ability.
Halfway through the battle, when Riku's health reaches about four bars, he will transform the Oblivion into a sword of light and he can no longer be staggered. His weapon's reach is now longer, making his combos harder to avoid. His Dark Aura ability will also be used after the transformation. It can be dodged by gliding, or by using Dodge Roll. If you are playing this battle with the Extreme Ring, Aero spells are your best bet against Riku. A stock of twenty to thirty Aero spells should allow you to take out Riku's HP, and if you miss with too many Aero spells, you should be able to finish him off with Event Horizon. The Neoshadows before the battle should be easy enough to get rid of, but when you fight the swarm, try activating Magic Hour, air-sliding away to allow movement, and then reactivating it after jumping high in the air.
One must be extremely careful during this mission. Even a single swing to the air counts as a missed attack. Limit Breaks can miss without penalty, as they are not standard attacks, but be sure to stop pressing when the Limit ends. Magic is also strongly recommended, particularly spells like Thundaga, which can hit a foe directly, even at a distance. Using Magic attacks only with Fire and Thundaga at LV5 with plenty of Elixirs to help restore them can also be a useful tactic as long as both spells have plenty of casts equipped. It is also recommended to use Magic against the Neoshadows that you fight before facing Riku due to their unpredictability of when they sink back into the ground to avoid attacks.
The Zero Gear should be equipped for this mission with three Ability Units. Use Limit Breaks to cut down Riku as quickly as possible. Since you have no recovery items or magic, Auto-Life is a must-have for this mission. Also make sure to keep an eye on Riku's moves at all times to help reduce the damage as much as possible. Both skillfully dodging and using Limit Breaks effectively are necessary to complete this difficult mission and avoiding Neo-Shadows attacks before facing Riku is just as important along with collecting the HP balls they leave behind. This mission may take multiple tries before you can get lucky enough to defeat Riku. Since there no level restrictions in this challenge, raising Roxas's level to increase the attack stat can also help.