Withering Winds (千年の風化, Sennen no Fūka?, lit. Millennial Weathering), also known as Millennial Decay, is a recurring ability in the series. It is the summon ability of the Final Fantasy IX incarnation of Fenrir, dealing massive Wind-elemental damage to all enemies.
Millennial Decay is the summon ability of Fenrir when Eiko is equipped with the Maiden Prayer, and deals major Wind-elemental damage to all enemies. It costs 30 MP to use and has a spell power equal to 44 + the number of Sapphires in the player's inventory (see here for damage formulae).
Withering Winds is an attack used by the Fenrir Magicite boss. It deals Wind-element damage to all party members and can inflict Slow. When summoned as an Esper, Fenrir can occasionally attack enemies with this move.