Mission 91: Escape the castle

Mission 91 in Kingdom Hearts 358/2 Days involves Roxas trying to escape from the Castle That Never Was in The World That Never Was.

Summary
Undocumented.

Objectives
Escape the castle!

Story summary
Roxas confronts Axel and becomes frustrated when Axel avoids his questions about himself, Xion, and Sora. They argue, which results in Roxas’s decision to leave Organization XIII. To do so, however, he must escape the Castle That Never Was. At the end of the castle is Saïx, who challenges Roxas. Roxas overpowers Saïx, leaving the Organization for good.

Mission walkthrough
Escaping The Castle That Never Was is very easy, as the path is very linear and easy to follow. Follow the path down and dispatch the Dusks you encounter. To reach the Ordeal Blazon in Naught's Skyway, jump from the top of the dual ramp and glide over to it. After taking the elevator at Crooked Ascension, head south through Nothing's Call. Samurais are along this path, but are easily eliminated with a weapon that boosts strength, such as the Ultimate Gear+. Continue south to meet Saïx.

Challenge Mission
This mission proves unchallenging until the player reaches Saïx. It is best to stay as far as possible from Saïx during the battle, especially when he goes into berserk mode. Glide is essential to escape his wrath. As far as battle strategy, load up as much Thundaga and Fire magic as is manageable, and attack repeatedly from a distance. Remember since you can't restore your magic casts in this challenge, be careful on how many casts are left on Thundaga or Fire. In addition, make sure to have a keyblade equipped with a high Magic stat. Also, while it is near suicidal to attempt to attack Saïx when he is in berserk mode, it is possible, on occasion, to sneak in a combo after he calms.

Rush to Saïx with the aid of at least Glide LV3 and quickly defeat him as fast as possible with a Limit Break. Use Cura and Limit Recharges if necessary. Remember if Saïx blocks your attack while using a Limit Break, stop for a second until he lowers his guard before resuming. Having Saïx drop out of berserk mode will also contribute greatly. The things that are necessary to get all 3 Challenge Sigils are fast strong arm tactics with barely any strategies combined with a high level and a Keyblade with high attack power, and it shouldn't be too hard to accomplish.