Trance Command. Use black magic twice.
FFIVTAY Fusoya and Golbez learn the Band ability Double Black Magic when fighting Zeromus's Malice, which acts similarly to Twincast. When used, Double Black Magic has a chance of using Twin Firaga, Twin Blizzaga, Twin Thundaga, or Twin Meteor.FFBE
Use black magic twice in one turn
Appearing alongside Dualcast, Dual Black Magic is an active special ability that costs 0 MP to cast and allows the user to cast any Black Magic spell twice in the very same turn Dual Black Magic is used. However, while ability itself does not have a MP cost, the spell that is used twice will drain the caster's MP. For example, using Firaga (which by itself costs 20 MP to cast) twice will cost 40 MP. Currently, Dual Black Magic can be learned by three units in the Global version: Vivi (at Level 60, 4★*3★ in the Japanese version), Arc (at Level 80, 5★), and Exdeath (at Level 80, 6★).
Other units, currently exclusive to the Japanese version, who learn this skill are: Victoria (at Level 1, 6★), Shantotto (at Level 1, 5★), Trance Terra (at Level 1, 5★), Sakura (at Level 1, 3★), the Emperor (at Level 80, 5★), and Dark Fina/Summer Dark Fina (at Level 94, 6★).