Ran Gotanda, younger sister to Dan Gotanda, appears as a recurring supporting character in the Infinite Stratos narrative. She attends Saint Marianne Academy as a third-year student council president and assists at her family's Gotanda Eatery alongside her brother.

Ran sports long scarlet hair tied in a high pineapple-shaped ponytail reaching her hips, with a slender build. At home, she favors loose attire like unzipped shorts and casual tops but switches to a white sundress with hair down whenever Ichika Orimura visits. She frequently clashes with Dan over Ichika yet shows deep care for her family. Holding a longstanding romantic interest in Ichika since middle school, she obsesses over minor details to attract his attention and vents frustration at his obliviousness to romantic signals.

In Episode 5, Ran wears revealing home clothes but flusters upon Ichika’s arrival, hastily changing into a dress. She denies his assumption that she dressed up for a date. During Episode 9, she buys multiple swimsuits at a mall, kicking Dan to silence him about modeling them for Ichika, and declares her intent to take the IS Academy entrance exam to become his junior. The OVA "A Sextet Yearning for Love" shows her interrupting a private moment between Houki and Ichika at a summer festival; after joining their activities, Dan calls her away before Houki’s confession attempt.

Ran views girls close to Ichika as rivals: she feels physically inferior to Houki Shinonono in bust size and appearance, engages in culinary competitions against Lingyin Huang’s Chinese restaurant to foster a neutral-to-hostile dynamic, and acknowledges mutual romantic advantages with Charlotte Dunois—Ran’s youth and hair color versus Charlotte’s figure and nurturing demeanor.

Her driving goal is enrolling at IS Academy via entrance exams to be near Ichika, a plan she reiterates while shopping and during family talks. Her mother Ren Gotanda supports this ambition and approves of Ichika, though Ren does not appear in animated adaptations.