Cloud of Darkness (Final Fantasy III boss)

Cloud of Darkness is encountered twice: first in a battle the party cannot win, and second at the very end of the game, where it's beatable.

NES Strategy
Since this is the final battle go all out here. Use all your Shurikens (make sure you reequip every round). Have the Sages cast Haste on the Ninjas the first round (if you have 14 or more Shurikens, you won't have to do that); after that, you'll probably have to have them cast Cure4 every round. If it seems like you have a round of respite, cast Baham. If you run out of magic, use Elixirs. Keep this strategy up and the Cloud of Darkness will eventually fall.

DS Strategy
One way of battling this enemy is just attacking the Cloud of Darkness' main body. But an easier way is attacking the right tentacle to rid the nuisance of using its Lightning attack. The right tentacles is completely immune to physical attacks but not magic. The left tentacle is immune to magic other than Bahamut's Megaflare and Leviathan's Tidal Wave, and must be taken down with physical attacks. The tentacles seem to be weak to water; Tidal Wave is preferable to Megaflare in this case. The Cloud of Darkness can use Bad Breath to hamper the party unless the characters are equipped with Ribbons or Aegis Shields. Otherwise, only its physical attacks pose an actual threat, until it starts to use Particle Beam.

A Devout is highly recommended for this battle due to their ability to use high level White Magic, including Curaja and Arise, more often and more powerfully than the Sage. Also, they can support the entire party with Protect or cast Holy on the Cloud of Darkness. However,Protect can only be cast on one person per turn so that strategy is optional. Warriors can use their Advance ability to deal heavy damage to either the right tentacle or the Cloud of Darkness; Ninjas are useful for their Throw ability and they can also inflict massive physical damage to the Cloud of Darkness while dual-wielding the Masamune and Muramasa.