Instructions
Defeat Cerebus in the Olympus Coliseum.
Talk to Cloud Strife as you leave the Olympus Coliseum--he will give you the Sonic Blade ability.
Press start to pause the game and enter the ̶0;Abilities̶1; section of the "Pause" menu. Scroll down to find ̶0;Sonic Blade̶1; and press the ̶0;X̶1; button to equip it.
Use Sonic Blade in combat when you̵7;re a few feet away from the enemy. A context-sensitive ̶0;Sonic Blade̶1; icon will appear in place of the normal ̶0;Attack̶1; icon. Press the ̶0;X̶1; button to initiate Sonic Blade.
Follow the on-screen prompts to use Sonic Blade̵7;s follow-through attacks. Continue to tap ̶0;X̶1; in rhythm with the on-screen cues and Sora will land a long succession of attacks, culminating in the powerful ̶0;Blast̶1; attack.