Behold, my children! She has heard our prayers! She is risen! The promised Ship of Light—the Lunar Whale!
The Lunar Whale's sprite is three to four times the size of the other airships, and it moves slower. Due to its size the ship cannot land in some places the Falcon and the Enterprise can and it is unable to enter the crater to the underground; if the player attempts to land the airship and enter the crater, the airship will lower and then rise back into the air, as it is too big to fit.
The ship was constructed by the Lunarian Kluya to travel between the Red Moon and Earth. After using the Lunar Whale to travel to Earth, Kluya put it to rest in the sea near Mysidia, at a point where the continent's shape forms jaws at the end of a dragon-like track of land. Thus the Mysidian Legend refers to the airship as "Birthed from womb of Dragon's maw, And borne unto the stars". The Mysidian Legend was passed down in Mysidia. Giott is also aware of the legend, but refers to it as explicitly a legend about the Lunar Whale.
Golbez acquires the world's Crystals and activates the Tower of Babil to call the Giant of Babil from the moon. The elder and the mages of Mysidia pray and create a great whirlpool from which the Lunar Whale rises to ferry Cecil and his allies to the Red Moon. The airship serves as transport for the party, and after Zeromus has been felled, is returned to slumber within the waters near Mysidia.
Porom and the Elder witness the Lunar Whale mysteriously rising from the ocean, and he sends her to Mount Ordeals to find Kain, fearful of what this means. In The Lunarian's Tale, it is revealed that Fusoya and Golbez called the Lunar Whale from the Red Moon, now adrift in space since leaving Earth's orbit. After the Mysterious Girl shatters their Crystals and declares her intent to travel to Earth, Fusoya and Golbez call the Lunar Whale, and Fusoya teleports Golbez aboard and sends him to Earth on it, staying behind to face Zeromus's Malice and his Big Bang attack.
During The Gathering Tale, the party reassembles and Golbez takes them to the Lunar Whale to travel to the True Moon and pursue the Mysterious Girl. If Golbez survives, he takes the Lunar Whale into space again to seek out the Red Moon and discover the fate of Fusoya and the Lunarians.
The ship's main chamber consists of an elevated deck hosting the Crystal of Flight that controls flight between the Earth and the Red Moon, with a control panel on the wall above the Crystal that allows the player to fly the ship manually. There are three staircases leading to a lower potion of the ship with a room containing healing beds shaped like pods, and a back chamber with a Fat Chocobo—in the 3D release the Fat Chocobo uniquely is mechanical. Unlike the other airships in the game, the Lunar Whale seems to possess no weaponry.
In The After Years, the second room with beds contains one bed, and the Fat Chocobo's chamber is removed and replaced with a staircase to a lower decks. The lower deck is similar in layout to to the top deck, with a save point in the second room and in the large chamber hosting four healing beds. Unlike Final Fantasy IV, the player is not free to return to Earth after traveling to the True Moon. As in other Final Fantasy games, the party members not currently in the party can be found wandering the decks and can be spoken to to prompt a change of party members.
The theme when the player is piloting or exploring the inside of the Lunar Whale is called "Lunar Whale", found as track 39 on the original SNES version soundtrack. For the English Final Fantasy Chronicles version soundtrack, the title was changed to "The Big Whale", which is also track 39. An arranged version appears in the Nintendo DS remake, now called "Magic Ship", which appears as track 15 on the second disc of that version's album.
The Lunar Whale can be seen in the far distance at the stage Lunar Subterrane as a background element next to the Crystal Palace. Its field icon is also used in the Duel Colosseum mode to represent higher level enemies.
The Lunar Whale is set to appear as a skin of the "Player Airship" during the update of May 16th, 2018.
Luna means "moon" in Latin, Italian, Romanian, Russian, and Spanish.
Thus the name stands for "moon whale", referring to its appearance and origin.
- As Kluya is stated to be the one who taught humanity how to build airships, it is likely that all the airships of the Final Fantasy IV universe are based on Lunar Whale specifications.
- On the North American website for the DS release of Final Fantasy IV, the Lunar Whale can be seen flying through the background of the menu backdrop.