Assassin

The Assassin is a high-ranking Nobody controlled by Axel that is found in Kingdom Hearts II.

Strategy
Assassins spend a lot of time in the ground. When they attack by flailing wildly, parry then attack.

If you can use the Reaction Command Fail-Safe, do so. This will make the Assassin explode, cause you no damage and still giving you Experience.

If you wish to fight powerful Assassins, the upper area of the Hall Of Empty Melodies in the Castle That Never Was is the only good place. However, in Kingdom Hearts II Final Mix, you can fight even more powerful Assassins in the Cavern of Remembrance.

Etymology
The Assassin is based on the Final Fantasy job class of the same name.