Sarah is a character from the Terra Battle series who appears as a guest party member in a Final Fantasy XV-Terra Wars collaboration added in patch 1.26. The player can gain her weapon by doing her quest. The quest "Close Encounter of the Terra Kind" is available from chapter 5 onwards, and the player can find it in the quest log.
Sarah has long gray hair with a white flower behind her right ear. Her ensemble is full of flower motifs from a flower on her forehead to the patterns of her white dress with a black bust. Her right arm has a guard with flower petal decorations and she wields a white one-handed sword.
Sarah is kind and motherly, though a bit naive and clumsy. She encourages Noctis to be more open with his feelings, as she is with hers. She is quick to befriend people and help those in need.
Sarah is whisked away to the world of Hiso Aliens where she meets Noctis. She is hurt and he heals her with a potion. She is thankful, but Noctis remains distrustful. Sarah asks for him to partner up with her to solve the mystery, and though Noctis is reluctant, the two explore the mystical forest ruins and discover the area is sealed off by magical barriers.
They meet a small white alien who explains the situation to the pair, although only Sarah can understand its language. Sarah and Noctis have been summoned to the forest by the Great Tree at the behest of the Hiso Aliens' elder, who wants two saviors from other worlds to save them from a monster known as the Eroder, who has been eroding their world.
Sarah and Noctis follow the alien and find statues coming alive to attack them. The two combine their skills to fight them off. They follow the alien to its village where a group of alien children steal Noctis's smartphone. Sarah rushes after them and gets the phone back, but when she helps an alien child hanging precariously over a waterfall, the tree they were on snaps. Noctis catches them midair and warps them to safety. He scolds Sarah for being so reckless, and she thanks him for his help.
On their way to meet the Elder, a tree comes alive and starts to attack, but Sarah saves Noctis from it and he again heals her with a potion. He is relieved and thankful. The Elder asks them to save the alien society from the Eroder, and the two agree to it, as if the Eroder is left to run amok, it would only be the matter of time until it could appear in their worlds as well.
The aliens remove the magic barriers for Sarah and Noctis to proceed to the coliseum, where the Eroder abandons its Hiso Alien form to copy Sarah's powers. Basking in its newfound powers the Eroder attacks and Sarah and Noctis fight it off together. After defeating the Eroder, it fades away, as do Sarah and Noctis now that their task is complete. Noctis is sad they must part ways and Sarah tells him to be more honest with his feelings toward his friends before it will be too late. Noctis says he will keep that in mind.
Sarah has 3412 HP and 100 MP, though the latter is only shown when she is briefly controlled (there are no battles at this time). The menu is unavailable so the player can't observe her equipment or other stats. The player can make her use items to heal herself.
Sarah's Technique is Salvation. It is a thrusting sword skill that can have a follow-up attack from Noctis. It costs one Tech bar to use and is the only Technique in the episode. It is unlocked after the second battle, after which Noctis and Sarah can also use link-strikes together. The player can still "link" with Sarah in the first battle, but the link-strike will fail because Noctis and Sarah are not "in sync": Sarah jumps onto Noctis who was not expecting it and he falls over, and both call out the other. During the confrontation with the quest's final boss, when using Sarah's Technique, Noctis confuses her with Prompto, Gladiolus, or Ignis.
Sarah can rescue Noctis from Danger. In the first battle, before the two are "in sync", Sarah rescues Noctis by leap-frogging over him, which makes Noctis topple over, or by running into him head first and the two fall down. After Sarah has gained Salvation, she rescues Noctis by simply touching him with her hand, like the party does in the main game.
After the Hiso Alien children steal Noctis's phone, the player can momentarily control Sarah to catch the kids.