On 21 June 2015, Kaiu Shirai published his first professional work, a
standalone piece called,
The Location of Ashley-Gate, in
Shōnen Jump+, a digital imprint of
Shueisha, with art by Kyousuke Maruyama. Again, in the same magazine, he published his second work, another standalone piece called, ''Poppy's Wish'', in collaboration with artist
Posuka Demizu on 18 February 2016. After that, Shirai created a serialized work based on drafts written while he was still an amateur. This work,
The Promised Neverland, (with art by Posuka Demizu) started its run in the 35th issue of
Weekly Shōnen Jump on 1 August 2016 and finished in the 28th issue of the magazine on 15 June 2020. Along with manga artist Posuka Demizu, Shirai published two one-shots in 2020 and 2021. The first one,
Spirit Photographer Saburo Kono was published in the combined issue No. 36 – No. 37, 2020 of
Weekly Shōnen Jump; the second one is titled
DC3, published in the same magazine in issue No. 35 of 2021. On 3 September 2021,
Kaiu Shirai x Posuka Demizu: Beyond The Promised Neverland was published, which included works and one-shots in combination with Posuka Demizu. A collaborative exhibition titled
Miroirs manga meets Chanel by Kaiu Shirai, Posuka Demizu and
Chanel was held at Chanel Nexus Hall Ginza,
Chūō, Tokyo, from 28 April to 4 June 2021. The manga
Miroirs, written and illustrated by the duo, was inspired by the Chanel brand. In this exhibition, scenes from
Miroirs are exhibited alongside precious works from Chanel. The manga was published by Shueisha on 30 April 2021. In 2022, Shirai participated as a judge at
Shōnen Jump+'s 7th Stokin Pro Garyokin 2022, to discover new talented manga artists. On 6 January 2024, Kaiu Shirai along with illustrator Shiki Hamada launched a standalone one-shot, titled
Kubigeshō, in the combined Issue #6–#7 2024 of
Weekly Shōnen Jump. Within the same year, on 9 December, Kaiu Shirai along with illustrator
Yōichi Amano launched a standalone one-shot, titled
Apple, in Issue #2 2025 of
Weekly Shōnen Jump. ==Influences==