Before you fight griffon the second and third times you should have picked up the grenade launcher at least and maybe by the third time you will have nightmare weapon-B. Don't use nightmare weapon-b on griffon cause it only wastes your devil gauge. Instead use the grenade launcher and change to devil mode, fire as many super-grenades as you can at griffon, then run in with the sword and slash it until your gauge fills up again, then run back and devil morph, and fires your grenades again to kill it. You don't actually need air-raid, or any special airborne attacks, and jumping doesn't help to much as you can't fire grenades and jump.