The Regis Hypothesis
There is a hypothesis that claims that the 3 Regis which are Regirock, Regice, and Registeel a represent Hibakusha.
In a Kotaku article titled Japanese Pokémon Fan Theory Links The Regis To World War II, this theory is covered and is even mentions it was recapped by a Youtuber called Kakeru. Theory goes that the Regi's locations are link 2 the 3 real locations in Kyushu, and the Pokemon needed to get there are could represent Little Boy and Fat Man.
The Kotaku article also brings up a website called Kowai Toshi Densetsu, which as an article that connects Regigas being found in Snowpoint city to Wakkanai, Hokkaido aka the home of the Monument Of Peace.
It also mentions a site called AniWota Wiki that brings up how the Regi's moveset of moves like Ancient Power and Hyper Beam, particualrly using their Japanesee names could also connect to this theory. Written by Eris