|“||The day after tommorow is my birthday.||”|
Kiyui's exact age is unknown, but he has the appearance of a toddler or preschooler. Kiyui has blue, often half-closed eyes and short blond hair with a single curl on his forehead. He wears the standard white shirt and baggy pants of the orphanage. He also wears a bell around his neck to signify his role as a Bell Whistle Delver.
Kiyui is a friendly and good natured child. Due to being very young, the other orphans are usually seen looking after him.
After Riko brought back Reg to the orphanage, he observes as the others inspect Reg and try to wake him up with an electrical shock, which causes a blackout. Leader catches him and the others, upon inspecting the blackout's source, and he is punished.
After Reg successfully manages to officially join the orphanage, he and Kiyui often spend time together while the others go cave raiding.
Before departing with Riko into the Abyss, Reg warns Kiyui not to look into the mirror on his birthday, fearing he may get Birthday-Death Disease. Kiyui does end up getting sick, but when Mio takes him to her ship to treat him, he seems to make an instant recovery.
Kiyui has theoretical knowledge about the Abyss, but has not made his first dive into it yet, presumably because he is too young.
- He is the only known survivor of the Birthday-Death Disease known so far.
- Kiyui seems to have formed a bond with Reg in the time they knew each other before Reg and Riko's descent into the Abyss. In fact, before Reg left, he visited Kiyui in his bed to say goodbye before sunrise.
- According to Akihito Tsukushi, Kiyui has a scent of dried saliva.
|Riko's Party||Riko • Reg • Nanachi • Prushka • Meinya|
|Belchero Orphanage||Belchero • Jiruo • Nat • Shiggy • Kiyui|
|Orth||Hablog • Laffi • Torka • Menae & Sherumi • Mio|
|Seeker Camp||Ozen • Marulk • Simred • Zapo • Yelme|
|Ido Front||Bondrewd • Gueira|
|Ilblu||Wazukyan • Belaf • Juroimoh • Vueko • Moogie • Majikaja • Maaa • Mitty • Poriyon • Mepopohon • Embellith • Shurekaka|
|6th Layer||Irumyuui • Ajapoka• Faputa • Gaburoon • Tepasté • Cravali • Srajo • Nishagora • Unknown Member of Hail Hex|
|The Abyss||Lyza • Srajo • Wakuna • Human-looking silhouette|
|Unnamed Characters||Minor Characters|