The spell may only be learned from a scroll of Thundaga II, which can be purchased from the merchant Susu in Lower Jeuno for 31,681 gil. Scrolls also drop off of Tonberry enemies and the Baron Vapula notorious monster. In addition, it can also be purchased from the player Auction House under the Black Magic category.
Thundaga II is an upgraded version of the original Thunder spell. It may be learned by Black Mages at level 61. When cast, it will deal Lightning-based elemental damage to all enemies in the targeted area for 200 MP. It takes 4 seconds to cast and can be recast every 10 seconds.
Thundaga II is used by the Boreal Coeurl boss in the Atop the Highest Mountains classic and elite dungeons in Final Fantasy Record Keeper. When used, the ability deals magic lightning damage to all targets.