Manga launched last year, runs in One Piece Magazine
The 12th issue of the One Piece Magazine "mook" series announced on September 2 that Boichi's One Piece episode A spinoff manga will end in the magazine's 13th issue, which will ship this winter.
Boichi (Dr. Stone, Sun-Ken Rock) launched the manga in the 10th issue of the magazine in summer 2020. Ryō Ishiyama (Amalgam of Distortion) is drawing the storyboards for One Piece episode A.
Shō Hinata's One Piece novel A series itself originally serialized in the One Piece Magazine. Shueisha published the story's two compiled book volumes in April and June 2018.
Viz Media is releasing the novel series under the title One Piece: Ace's Story, and it describes the story:
Get the backstory on Luffy's brother Ace in this first of two prose stories that continue the high seas adventure ONE PIECE! This volume contains the origin story of Luffy's adopted brother Ace, and tales of his thrilling quest for the legendary One Piece treasure.
Boichi previously drew a one-shot for One Piece in 2019 that "covered" a chapter from the original manga.
Source: One Piece Magazine issue 12