After Empress Hazel defeated Sora and Riku and left for Far Far Away, Sarah appeared on Destiny Islands, looking for Sora. Kairi tells Sarah what happened and offers to help her find Sora, which she begrudgingly accepts. Later, Sarah finds Sora in Neo Asgard-III, just as it had been occupied by Hazel, and helps him beat Loki before introducing herself. They discover that Hazel has agents in the neigboring eight worlds, but are only able to go to four of them to seal their keyholes.
Sarah's appearance is basically a Tetsuya Nomura-style cariacature of her real-life counterpart and voice actress, with a bigger bust and more shapely figure. She wears multiple outfits in between appearances, including those of other characters like Tifa Lockhart.
- Tifa Lockhart (FFVII & FFVII:AC)
- Rinoa Heartilly (FFVIII)
- Yuna (FFX-2)
- Darla Dixon (an OC conceptualized for The Walking Dead by Sarah Cowan)
- Kasumi (Dead or Alive)
- Kokoro (Dead or Alive)
- Hitomi (Dead or Alive)
Also, in some of the worlds she visits with Sora, Sarah's outfit or appearance changes as follows:
- Poultry Prison: Aardman-style goose/swan with her Darla Dixon attire.
- Ratropolis: Aardman-style rat with her Darla Dixon attire.
- El Dorado: Marle outfit
- Mythic Ocean: Nami outfit
- Monster/Alien Battlegrounds: Lucca outfit
- Berk: Irina Sykes outfit
- Croodlands: Ayla outfit
Sarah is an overall complex character, who despises Kairi, a trait of which she is rather outspoken, yet exhibits positive qualities such as bravery, compassion, wittiness, valuing frienship, maintaining a bright and cheery demeanor, and a dislike for bullying and disciplinarianism. She also idolizes and has a big crush on Sora, often flirting with him playfully or fantasizing about him, and desires to marry him despite his commitment to Kairi. Her favorite hobbies include cosplaying, gaming, modeling, singing, sewing, and writing romantic fan fiction involving herself and Sora.
Sarah is also autistic, meaning she has trouble giving attention to certain subjects, and does not respond very quickly, though it's usually because she wants to think carefully before she speaks her mind. Her autism does not, however, inhibit her optimism, and Sora shows her the utmost sympathy in light of this.
- "Eight Princess of Light! Sarah Serenity!" - announcement
- "What I want most in life is to love and be loved in return......to be happy and bring happiness to those I love."
- "Don't be scared, be hopeful."
- "If you give up now, then the battle is already lost."
- "You wouldn't know fun if it took a dump on your face!"
- "What am I, the human iPhone!? Stop bossing me around!"
- Sarah's relation with Kairi is extremely similar to that between Squidward Tentacles and Spongebob Squarepants. Also, the running gag about her wanting to marry Sora despite his inhibitions is exactly the same as Amy Rose's own infatuation with Sonic the Hedgehog .
- Her seiyuu, Juri Miyazawa, was on Seijuu Sentai Gingaman(one of GokaiWhite's favorite Super Sentai seasons) as Saya/Ginga Pink.
- Her dressing up as Final Fantasy and Dead or Alive characters is an homage to the fan series Dead Fantasy, which GokaiWhite is now interested in continuing or rebooting. Either way, he hopes to include Sarah as a main character.
- If Sarah is considered a Disney Princess (by proxy), then she would be the first one with a mental disability.