Oathkeeper & Oblivion

When Roxas uses his full power, he wields both Oathkeeper and Oblivion. His strength greatly increases when used. The combination of these Keyblades is first used in Kingdom Hearts II when Roxas battles Axel for the second time. It can also be used in the last mission of Kingdom Hearts 358/2 Days, before Roxas's battle with Riku. In the Mission Mode of Kingdom Hearts 358/2 Days, equipping the Zero Gear with 3 ability units attatched will result in a hodded Roxas wielding Oathkeeper and Oblivion. Roxas gained the ability to use both of these weapons at once after the death of Xion.

Trivia

 * You can't Dual-Wield Oathkeeper and Oblivion in Kingdom Hearts 358/2 Days's Story Mode. Equipping the Zero Gear with 3 ability units in Story Mode will result in the Kingdom Key+.
 * When Dual-Wielding Oathkeeper and Oblivion in Mission Mode, Roxas is very weak compared to his strength during the last mission in the game's Story Mode, before the battle with Riku, where he can destroy Neoshadows rather easily.
 * Roxas's ground combo with the Oahtkeeper and Oblivion in Kingdom Hearts 358/2 Days is exactly the same one from his data battle in Kingdom Hearts II Final Mix.
 * When Roxas Dual-Wields Oathkeeper and Oblivion in Kingdom Hearts II, his ground combo is different than that of when you fight him in Kingdom Hearts II Final Mix.