Battle:
https://www.youtube.com/watch?v=54FgoUdV2S4Overworld:
https://www.youtube.com/watch?v=K8AdrYxFbroHe started the "great war" that it is suggested to have occurred before Kanto, being made possible due to the rise of Pokémon technology. This allowed him to catch and control dangerous legendary Pokémon.
He killed many in an effort to seize control of the globe. He was eventually stop, but many of his ideologies linked their way into the criminal organizations that would occur in later games. All history concerning him was scrubbed, forgotten, and with his collapse condition the existence of the Pokémon league which was designed to have champions from every region have the power to defend against something like this ever happening again. And this is why many of the champions are involved in tackling these issues. The first champion, defeated him.
