In Kingdom Hearts Birth by Sleep, Last Word is a Finish command. The user charges in the direction they are facing. Therefore, the user may miss the attack by not facing and being locked on to an enemy. Also, if the user is too close, it is possible to push an enemy out of the way with the light columns at the start of the attack. A successful execution of Last Word is the only way to finish the final battle against Vanitas.
In Kingdom Hearts III, Last Charge is an action ability that costs 7 AP to equip. It is a combo finisher that deals a devastating blow. Sora charges forward and performs a quick forward slash that creates a pillar of light that causes enemies to reel. If performed in the air, the pillar also shots downward and can hit enemies below. Its damage is determined by Sora's Magic stat. Equipping this overrides Magic Flash.
Learning Last Word
Kingdom Hearts Birth by Sleep
Kingdom Hearts III
Notes and references