- 伊达·赫克斯特（イダ.ヘクスト Yda Hext），出生在阿拉米格的伊达至今仍然是个谜团，但这并不能掩盖她卓越的才能，尽管所有人都对她所知甚少，人们仍然能够描绘出她与她人一般多彩的人生历程。
- Yda is found with Papalymo laying in the Black Shroud, after ejecting from their airship and welcomed into Gridania after being found by the Adventurer. The conjurers of town are lead to believe that the duo is beckoned by the elementals, and therefore are expected to do something for them, a fact that makes Yda proclaim herself as a "Savior of the Wood".
- During the course of Gridania's storyline, she is often seen with the conjurers preparing for the great ritual set to happen in the city-state.
- In the final mission, she and Papalymo are the ones responsible for finding Dunstan and bringing him back into town. After the ritual, the Echo reverberates and the skies turn black, a fact that makes Papalymo comment with Yda that they "should've stopped it, and now it's too late", to which she replies that they still can find a way to stop it.
- She is not seen again until the eleventh mission, "Futures Perfect", where she joins forces with Papalymo, Y'shtola, and Thancred in their fight against the Imperial Legatus. She is notably the only character to land a hit on the Garlean general. If the Adventurer's home nation is Gridania, she and Papalymo are the ones who appear at the end of the mission, telling about the greater power needed to defeat the Garleans.
- Yda, Papalymo and Kuplo Kopp are first encountered during the "Chasing Shadows" quest, inspecting the disturbance in the aetheric flow inside the Central Shroud. While speaking to the Adventurer, they are attacked by a group of Treants. The two help the Adventurer fight the attacking Treants and they manage to defeat the monsters. After defeating the monsters, Yda and Papalymo watch over the Adventurer after they faint from a surfeit of aether.
- After the Adventurer wakes up, Yda discovers the corpse of a Chieftain Ixal and she and Papalymo suspect that it was the one responsible for the monster attack. Papalymo then orders Kuplo Kopp to report to E-Sumi-Yan about the situation. After Kuplo Kopp departs, Yda and Papalymo bid the Adventurer farewell and return to report the situation to their leader.
- Yda and Papalymo are not seen again until the Adventurer is at the Guardian Tree during the "To Guard a Guardian" quest. During the quest, Yda and Papalymo arrive to aid the Adventurer during the battle against the Masked Mage and its Lesser Gargoyle. After defeating the the Masked Mage, Yda and Papalymo discover that it is the Ascians who have been manipulating the beast tribes.
- During this time, Yda reveals to the Adventurer that she and Papalymo are actually Sharlayans and that they have been helping the Gridanians for the last five years. Papalymo begins to suspect something, but refuses to speak about it to Yda at the current moment, much to her annoyance. Yda and Papalymo then say goodbye to Adventurer and return to Gridania. After returning to Gridania, both Yda and Papalymo are seen at the Greenbliss festival in the city and congratulate the Adventurer.
- Yda and Papalymo are not seen again until "The Scions of the Seventh Dawn" quest in Western Thanalan. It is here that the Adventurer learns that they are part of the Scions of the Seventh Dawn, a group formed of the Archons and the Path of the Twelve.
- She is one of the few Scions to evade capture by Livia sas Junius after the Garlean Empire attacks their headquarters at the Waking Sands.
- After the success of Operation Archon and the defeat of the Ultima Weapon and Gaius van Baelsar, she continues her duties with the Scions, supporting the Adventurer whenever their activities lead them to the Black Shroud.
- When the Scions are betrayed by the Crystal Braves and framed for the assassination of Nanamo Ul Namo, she stays behind with Papalymo to buy enough time for the other Scions to escape. During the ensuing battle, her mask is broken, revealing part of the covered portion of her face for the first time. She and Papalymo are presumed dead after they stay behind to hold off the Scions' pursuers, however neither the bodies of her or Papalymo are found amongst the dead in the aftermath. Their linkpearls would later be found in the streets of Ul'dah, deliberately stepped on and destroyed.
- During the final quest of patch 3.1, Yda, along with Papalymo are shown to be gathering in a cave along with many others, in what is likely a preparation by the Ala Mhigan Resistance for an attack on the Garleans. Papalymo mentions that they can't stay here forever, as they have other responsibilities.
- Papalymo is seen urging Yda to consider the "Masks" carefully and find out more about their goals, to which she nods in silent agreement.
- Alphinaud and the Warrior of Light reunite with Yda and Papalymo at a rally held by the Masks. They explain how they came to be involved with the Resistance, and what they know of the Masks. They agree to arrange a meeting with The Griffin's proxy, a double posing as him at the rally. Through this they learn of a gift of crystals intended for Amalj'aa, leading to a fateful confrontation with the Warriors of Darkness.
- Outside Little Ala Mhigo, Gundobald greets Yda, who claims he and her father used to fight in the Resistance.
- "So, this is it. Whatever I choose to do from now on, I do as Lyse. ...And I choose to continue my family's fight. I want Ala Mhigo to be the country that Yda and my father always wanted it to be!"
—Lyse, after revealing her true identity.
- A friend of hers in the Ala Mhigan Resistance, M'naago, arrives at the Rising Stones wounded. As she is treated, she warns the Scions that The Griffin is plotting to attack Baelsar's Wall. Yda travels with Papalymo and Yugiri in secret tunnels to try to reason with the Griffin. Once his true intentions became apparent, Alphinaud rushes after them. They eventually catch up with the Warrior of Light upon the Wall, who just defeated the Griffin. The man reveals himself to be the traitor Ilberd. Having not only came into possession of the Eyes of Nidhogg, his true goal was to sacrificed his soldiers and even himself to summon a primal against Garlemald.
- As the primal began to manifest from the dying life energies of the soldiers and the Eyes, Papalymo orders everyone else to flee while he walks the path he must follow. Yda desperately protests what he is planning and asks to stay by his side. Understanding what Papalymo is going to do, Thancred forcibly carries her back to Hilda's airship as a cocoon of light engulfs the manifesting primal and Papalymo. Sullen and grief-stricken, Yda watches over the shell with Y'shtola and Yugiri at the East Shroud.
- The Warrior of Light teams up with Nero tol Scaeva and uses the dormant Omega to defeat the primal Shinryu which births from the shell. Following the encounter, with the last of Papalymo's aether having left the world so too does the tattoo on Yda's neck disappear; A fake created by Papalymo's magic. With Papalymo truly gone Yda reveals the truth about herself. That the real Yda died six years ago and her true identity is Yda's younger sister Lyse. Y'shtola admitted to have known Lyse's identity from the moment they met and that she and the others agreed to keep up the charade at the request of Papalymo. Lyse decides to honor Papalymo's final words to her by acting under her true name and fighting for the freedom of Ala Mhigo.