-Note: You should already have the strongest ground attack. When facing the Griffin, hold BLOCK then hold down the key that controls your sand powers. While holding these, charge up until your ground attack is at maximum. This should automatically send out its shockwave, dealing a great amount to the Sand Griffin. Do this about three to four times and it should die.
-When the fight begins, trigger your ground attack twice. This should get him to half health. Then, run in circles until you have a new Sand Tank. Then, charge him and try to avoid his attacks. When he gets in the air, just hang on the edge. He cannot reach you. When he gets back on the ground, Slow Time and attack him. He will eventually be defeated.