Naoki Urasawa's 20th Century Boys, Volume 5: Reunion

This is the story of a gang of boys who try to save the world!
As boys, Kenji and his friends came up with a bunch of stories about an evil organization bent on world destruction. As adults, someone is now turning their fantasies into reality!

The giant robot has already been built and now awaits the Great Awakening... With the Friend's identity still a mystery, the countdown to the apocalypse continues, day by day, minute by minute — for on December 31, 2000, humanity will meet its final hour. Hoping to get as many people who knew about their group's emblem involved in their clandestine efforts, Kenji's crew reaches out to their childhood antagonists: the twins Mabo and Yanbo. Back when they were kids, Yanbo and Mabo terrorized Kenji and company to no end. As adults, and with a crisis looming, will the evilest brothers in history now fight on the side of good? Humanity, having faced extinction at the end of the 20th century, would not have entered the new millennium if it weren't for them. In 1969, during their youth, they created a symbol. In 1997, as the coming disaster slowly starts to unfold, that symbol returns.