Tatsuya Endo was born in Ibaraki Prefecture, Japan, on July 23, 1980. He debuted as a manga artist with the one-shot "Seibu Yugi" (Western Game), which ran in the Spring 2000 issue of Akamaru Jump. He is the author of Tista and Blade of the Moon Princess. Spy x Family is his first work published in English.

Aya Yajima is an author who has written novel adaptations of several best-selling manga series published by Shonen Jump’s novel division. She began her professional career in 2011 with a series of novels for Blue Exorcist. In 2019, Yajima then began writing the novel adaptations for the hit series Demon Slayer, and in 2021, she partnered with manga artist Tatsuya Endo to write the first novel for Spy x Family.