"Cloudian - Smoke Ball" (above) and "Cloudian - Turbulence"
"Cloudians" require an advanced degree of skill to use properly, because their usefulness depends on how many Fog Counters there are on the field. Most "Cloudians" cannot be destroyed by battle, but their low ATK leaves their controller open to taking damage unless "Spirit Barrier" or "The Sanctuary in the Sky" are used. Once your support cards are in play, the opponent will find it frustratingly difficult to get past a "Cloudian" Deck's defenses. While the opponent is being stalled, the "Cloudian" user can then generate enough Fog Counters to whittle down the opponent's defenses, eventually leaving them with nothing to protect themselves from the otherwise "weak" monsters.
A "Cloudian" Deck can focus on swarming the field, on destroying the opponent's cards, on inflicting effect damage with "Natural Disaster", on a Stall Victory, on raw Beatdown power with "Cloudian - Nimbusman", or any combination of the above. "Cloudian - Eye of the Typhoon" can also provide some field control by messing with the battle positions of opposing monsters. The seemingly weak monsters in the Deck such as "Cloudian - Altus", "Cloudian - Cirrostratus" and "Cloudian - Acid Cloud" become surprisingly useful with enough Fog Counters on the field. Through cards like "Cloudian Squall" and "Fog Control", anyone facing these three puff-balls will quickly find themselves with no monsters, no back row, no hand and no options. Hence the name: "Cloud Control". A killer combo can be made by using "Cloudian Squall" to put a Fog Counter on "Cloudian Turbulence" every turn. Then you can play a "Cloudian Smoke Ball" and tribute it to play "Mecha Sea Dragon Plesion", and every turn tribute the "Smoke Ball" that you can play each turn to devastate your opponent's field.
Also, since most "Cloudians" are Fairy-Type, a good card to add is "Athena", who can use her effect to Special Summon powerful "Cloudians" from the Graveyard by sacrificing smaller "Cloudians" like "Cloudian - Smoke Ball". While the Special Summoning is generally a good idea, bear in mind that most "Cloudians" gain their Fog Counters when they are Normal Summoned.
The effects of the "Cloudians" work when they have enough Fog Counters to pay for them. The number of Fog Counters they get depends on the number of "Cloudians" on the field when each "Cloudian" is Normal Summoned. Since they have many cards to quickly Summon Cloudians like "Cloudian - Sheep Cloud" and "Cloudian - Turbulence", they can quickly swarm the field. The strength of the "Cloudians" lies in their ability to destroy cards using the Fog Counters, limiting the opponent's ability to respond.
These are the main power source for "Cloudian" monsters. These counters should be placed mainly on the "Cloudian"-player's monsters but certain "Cloudian" cards can take advantage of Fog Counters anywhere on the field (e.g. "Cloudian - Nimbusman", "Diamond-Dust Cyclone").
"Cloudians" generally gain Fog Counters when they are Normal Summoned. Cards like "Ultimate Offering" help generate huge masses of Fog Counters on several monsters in no time at all, allowing for immediate use of their appropriate effects. Since Fog Counters can only be placed on face-up monsters, "Light of Intervention" is a good card to use in a "Cloudian" Deck. A good way to gradually strengthen your monsters is to have "Cloudian Squall" out and stalling tools to buy turns for accumulating Fog Counters.
"Cloudian" Decks are often underestimated because, while most of the "Cloudians" cannot be destroyed by battle while in Attack Position, if they are in Defense Position they are destroyed by their own effects.
It wouldn't hurt to add a "Gozen Match" or "Rivalry of Warlords" in the Side Deck as nearly all the monsters are one Type and most of them are one Attribute. If you know what type of Deck your opponent uses, you could slip in one (or both) of the above cards to limit your opponent's Summoning abilities while leaving yours almost untouched.
Another helpful card in a "Cloudian" Deck is "Mira the Star-Bearer". Its effect protects your "Cloudian" monsters from being destroyed, and it's fairly simple to summon with "Cloudian - Turbulence". If you choose to play "Athena" then a good card to use is "Valhalla, Hall of the Fallen"
This Deck used "Cloudian - Turbulence", "Cloudian - Smoke Ball" and "Cloudian - Storm Dragon" to swarm the field. "Smoke Ball" can be tuned with "Fishborg Blaster" to Summon "Formula Synchron" and "Storm Dragon" is used to Synchro Summon any Level 5 Synchro Monster. Then you can Synchro Summon "Shooting Quasar Dragon".
While "Cloudians" cannot be destroyed by battle while in Attack Position, "Zero Gravity", "Stumbling, "No Entry!!", "Earthquake" and "Spider Web" would cripple this Deck as the these cards forces all monsters to Defense Position making the "Cloudians" destroy themselves. An opponent using a well-timed "Windstorm of Etaqua" can effectively destroy all "Cloudian" monsters. "Spiders" are also a threat, because they change the Battle position of a monster to Defense Position. "Savage Colosseum" also gives trouble, because all "Cloudian"s will be obliged to attack and they will be destroyed by a card's effect instead of by battle (quicker results can stem from use of cards like "King Tiger Wanghu", "Doom Donuts" and "Deck Devastation Virus.)