Iutycyr Tower

The Iutycyr Tower [] is an exclusive dungeon only available in Final Fantasy X-2 International + Last Mission and Final Fantasy X-2: Last Mission HD Remaster.

The tower dungeon's layout is similar to Via Infinito. It has 80 levels in total, and at every 20th level the player has to fight a boss. On every tenth level, Yuna, Rikku and Paine will have a conversation about what has happened since the events in Final Fantasy X-2.

Story
Three months after defeating Shuyin and Vegnagun, the Gullwings members have gone their separate ways: Yuna is living with Tidus in Besaid, Rikku is working mission after mission, and Paine is wandering Spira by herself. They are brought back together after each received a letter that called them to explore the newly discovered Iutycyr Tower.

As the trio explores the tower ruins, they converse over what they'd been doing since they had separated, and why they hadn't stayed in contact. The conversation escalates as Rikku expresses her jealousy towards Yuna who had reached her goal in life and settled down. The bickering between the pair causes Paine to raise her voice against them. Eventually, Paine reveals she was the one who sent the letters citing it was her wish to not lose the friendship they once shared, having learned from both her previous friendship with Nooj, Gippal, and Baralai, and from her own lonely travels.

On the final floor the trio encounters Major Numerus, who appears to be sealed or out of order prior the disturbing of its slumber.

Before attacking the party "CAUTION", "KEEP OUT" and the following verse (a possible reference to the "spiral of death"):
 * each new death holds
 * the promise of life
 * each new life brings
 * the promise of death
 * the circle is unbroken

in Spiran script can be read on his body. Major Numerus has to be defeated three times before the final stair can be climbed.

The trio travels to the top of the tower where they find a broken machina, whose upper part slightly resembles Sin, and not much else. The trio realize the machina resembles their group: broken and separated. As they vow to be more than just strangers who met by chance, becoming friends once again, the machina springs to life and their adventures continue...

Scaling the Tower
Moving and battling in the tower is done differently from the rest of the game. Everything is turn-based, similar to Chocobo's Mysterious Dungeon. Fiends appear on the map, the player chooses their action (which can be moving, changing dresspheres etc.), then the fiends will take an action. Finding an elevator will allow the player to advance to the next floor.

Teaching the 10th, 20th, 40th, 60th and 80th floors earns a new trophy in the Final Fantasy X-2 HD Remaster version.

Musical Themes
The themes that play during the player's trek within Iutycyr Tower are called "Last Mission No.1", "Last Mission No.2" and "Last Mission No.3". The tracks appear in the Final Fantasy X-2 International + Last Mission Original Soundtrack as tracks 4, 5 and 6 respectively.

Etymology
In the Japanese version, "yadonoki" is an Al Bhed translation of "maboroshi", meaning phantasm or illusion. In the English version, "iutycyr" is reverse Al Bhed for "eidolon". Eidolon is a Greek word for "unsubstantial image" or "phantom", and has been used as a name for summoned monsters in some installments to the Final Fantasy series.

Before the release of Final Fantasy X/X-2 HD Remaster, the tower had been given an alternative English name, as found on a collectable card: "Abrasanym", Al Bhed for "ephemeral". Incidentally, the adjective "ephemeral" is used for manikins of Final Fantasy X characters in the Dissidia games.

Trivia

 * If the file used during the Last Mission playthrough is 100% file, an unlockable video will become viewable through the main menu.
 * Iutycyr Tower's location in Spira is never revealed, but the presence of tropical foliage suggests that it's in the south of Spira, near Besaid and Kilika.
 * There are no symbols associated with Yevon found in the tower, making it possibly older than Zanarkand and Bevelle.