Iro Aida is the joint pen name of a Japanese creative duo consisting of the writer Iro and the illustrator Aida. Together they are the original creators behind the manga and anime series Toilet-Bound Hanako-kun and its spin-off, After-School Hanako-kun. The duo’s name combines their individual roles, with Iro credited for the story and Aida for the artwork. Before adopting their current pen names, Aida previously used the name Aida Hano, while Iro used Tokuna Nozomi.

The partnership between Iro and Aida dates back to their school days, where they were classmates before beginning their professional collaboration. Their earliest known major work is the visual novel Narisokonai Snow White (Half-Baked Snow White), which was released in February 2011. In the years that followed, they produced several one-shot manga, including Nika Kiri! in 2012 and Dear My Living Dead in 2013.

Their breakout work, Toilet-Bound Hanako-kun (Jibaku Shōnen Hanako-kun), began as a pilot series from June to August 2014 before commencing full serialization in Square Enix’s Monthly GFantasy magazine in December 2014. The series follows Nene Yashiro, a high school girl who summons the ghost Hanako-kun from a school bathroom and becomes his assistant in maintaining the balance between the human and spirit worlds. A lighter-hearted spin-off manga, After-School Hanako-kun (Houkago Shōnen Hanako-kun), began serialization in February 2018.

The success of the manga led to multiple anime adaptations. The first anime season of Toilet-Bound Hanako-kun, produced by studio Lerche, aired from January to March 2020. A new anime project described as a restart of the series was later announced, beginning with an adaptation of After-School Hanako-kun that aired in 2023 and 2024. A second season of the original anime followed from January to September 2025.

The artistic identity of AidaIro is characterized by a retro-inspired visual style, notable for its distinctive use of color and expressive character designs. Their work often balances lighthearted comedic moments with darker, more atmospheric supernatural storytelling. The duo has maintained a consistent serialization schedule with minimal interruptions for over a decade.

Within the industry, Toilet-Bound Hanako-kun has achieved significant commercial success, with over 10 million copies in circulation as of February 2024. The series has been published in English by Yen Press and has garnered an international following.