The hideous, darkly clouded form of Famfrit, scion in opposition to Holy Queen Emmerololth, scion of light, was anathema even to his creators. Thus, after a great battle, was he broken and sealed within armor laced with wards. The confines of his armor are void of light, and so is he called the Darkening Cloud. Men fear the rain that falls from the black clouds that ooze from that giant ewer as a herald of chaos and waste.
Famfrit is fought alongside with Dr. Cid, who is immune to everything when Famfrit is summoned. Famfrit mostly attacks with magick. Famfrit's standard attack, Briny Cannonade, deals Water damage on one character, and his special attack, Waterja, deals Water damage to characters in range and has a chance of inflicting Silence.
Dr. Cid will buff Famfrit from time to time. He can also use his S-85 Cyclotrone and Gatling Gun while the party is fighting Famfrit, although it is easily dodged by going behind him. After defeating Famfrit, Dr. Cid's paling will fall, and he can be easily beaten.
The first move is to dispel Famfrit's buffs. Hopefully, Reddas is targeting Famfrit, and not Dr. Cid. Using Shell is useful. Famfrit's vulnerability to Oil can be abused with Fire-elemental weaponry, like the Gungnir, or a Fomalhaut with Wyrmfire Shot. Equipment with affinity to Fire can boost the damage further. One should also consider summoning the EsperBelias for an Esper vs. Esper battle, since Belias's Fire attacks can do massive damage against Famfrit.