The Tempest Bow can be brought into the battle against the Elder Wyrm in Tetyth. Fia's Giga Drive does a significant amount of damage and helps to shorten an otherwise protracted battle. Alternatively, it can be brought into the Red Sage battle, but the player will have to hold on to it till near the end of the chapter. Lina's Gigantic Bolt does poor damage and is not recommended.
Even though the infobox states 'Random Enemy B', it is more accurately described as 'Random Enemy A' as all four hits of Giga Drive always hit the same random enemy.