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.