Aki Haruka, operating as the superhuman Arachne, was an idol within Imperial Ads' Angel Stars group. Her distinctive green hair transitioned from short to long during her tenure. She noted the linguistic significance of her name, referencing its potential seasonal meanings ("spring or autumn").

Her personal life included a romantic relationship with fellow Angel Stars member Fanny. Imperial Ads terminated her contract, citing the relationship's incompatibility with commercial idol expectations. This scandal forced her departure from Angel Stars, resulting in significant personal turmoil and disillusionment with societal constraints.

Plunged into despair and isolation, she expressed a desire to escape societal pressures. This vulnerable state made her a target for the Fumers, extraterrestrial entities seeking ideal superhuman hosts. Contemplating surrender to their possession, she saw it as an end to her suffering.

Her crisis intersected with Jirou Hitoyoshi. She openly challenged his ideals, critically referencing how "this nation's sense of justice" – championed by previous generations – had become an empty justification for discrimination and control. Her confrontation underscored the tension between institutional authority and individual freedom.

Ultimately, she chose to remain with her Angel Stars bandmates despite ongoing challenges. This decision followed a pivotal moment acknowledging the value of human connection over isolation, though she continued concealing her emotions behind a performative facade. Her narrative explores societal oppression, LGBTQ+ discrimination, and the exploitative nature of the idol industry.

Her character arc illustrates themes of alienation, the search for authentic existence, and the complex negotiation between personal identity and societal expectations. Her experiences critique systems enforcing conformity at the expense of individual dignity and love.