However, when it comes to portraying himself & his assistants... Kurumada loves taking the Mick, for those who speak the Queen's English.
While I'm not sure when exactly it came about, though I imagine it was in part due to the ongoing success of Ring ni Kakero, Masami Kurumada eventually hired on a group of assistants, comprised of some combination of Jun Tomizawa, Toukichi Ishiyama, Tokumi Kawajiri, Takashi Urakawa, Masayuki Fujimoto, Chuutaro Numoto, Masashi Yamaguchi, & Ken Shiratori over the years. Kurumada would name this group "Shinwakai/The Gathering of Gods", and even listed Shinwakai alongside him for new chapters as they originally ran in Weekly Shonen Jump (as seen via the Ultimate Final Edition of Fuma no Kojirou); at the very least, he did this for both Ring ni Kakero & Fuma no Kojirou. While the concept of assistants that help a main mangaka out getting a collective name can arguably date back to Tokiwa-sou, the Tokyo apartment building that in the 1950s housed Osamu Tezuka & other legendary mangaka (some of which even initially worked as assistants to Tezuka, introducing the very concept), Shinwakai can be seen as the precursor to arguably the most well-known named group of assistants in Jump history: The Watsuki-gumi from the 90s who assisted Nobuhiro Watsuki on Rurouni Kenshin, which was comprised of Eiichiro Oda (One Piece), Hiroyuki Takei (Shaman King), Shin'ya Suzuki (Mr. Fullswing), the late Gin Shinga (who passed away in 2002 at only age 29), & Mikio Itou (who's probably most known for cameoing in his fellow Watsuki-gumi's works, like One Piece, as a travelling merchant).
However, as legendary/notorious as the Watsuki-gumi were back then, & (some) still are now, they never got to star in their own manga!