Ikushima attends Sanada East High School and forms a core trio—the High School Girls Are Funky group—with Yanagin and Habara. She readily participates in Yanagin's unconventional ideas, though her involvement isn't absolute; she sometimes balks at Yanagin's level of vulgarity. Her pre-high school background remains largely unspecified, though she met both Yanagin and Habara during middle school. Crucially, she was unaware of Habara's middle school reputation as the "Archdemon," indicating she joined their social circle after the significant conflict involving Habara. Visually, Ikushima sports dark blue hair typically in twin tails and black eyes. Her standard outfit is the Sanada East High uniform: a white long-sleeved shirt under a grey sweatshirt, paired with a red-brown plaid skirt, navy blue knee-high socks, and penny loafers. Personality-wise, she is naturally cheerful and energetic, often buzzing with hyperactivity. While she actively engages in or contributes to Yanagin's absurd whims, she maintains greater restraint than her friend. She shares the trio's aversion to stereotypical high school boy behavior and openly criticizes it. However, she distinguishes herself by occasionally expressing a desire for romance, revealing a more conventionally feminine side. Her known abilities include excelling at wrestling, which she continues in high school, and possessing practical culinary experience.