Rai was first published as 4 mini-stories in Magnus 5 through 8. When Rai got his own book, it had run 9 issues by 1993. Shooter had a hand in writing issue 7 and the all important issue 0.

The vision of Valiant was very prevalent when Rai 0 was released two months after Unity, a book that left fans in awe. The issue was less a story and more of a Valiant universe bible, foretelling events anywhere from one to ten to a thousand years away. The book would start off introducing a new Valiant character, a bald man named Bloodshot, who would kill his captors and escape thanks to a Geomancer.

The book would quickly move on to 1999, where readers would learn that fan favorite Shadowman would die fighting a villain named Master Darque. Years in the book leaped quickly as the reader moved panel to panel, nearly learning the demise of most of Valiant's famous characters before moving to the year 4002, introducing a new Rai and leading into a new Rai series. [source]

Background on Rai:
Since the thirty-first century, and for a thousand years thereafter, a successive line of extraordinary men have assumed the mantle of "Rai", the national protector of Japan. Now, with Japan shattered and Earth being conquered, one man has become the last Rai--seeking to defend not a nation, but the entire planet from the Malev threat...

Tohru Nakadai is the forty-second man to become the Japanese national champion. It is "Grandmother", the sentient computer caretaker of Japan, that transforms Tohru into Rai, imbuing him with vast and powerful energies.

During Tohru's tenure as Rai, the Spider Aliens invade Earth for the second time. Controlled by Grandmother, the enormous robot-body that covers the Japanese islands is brought to bear against the alien starships. The alien armada is destroyed, but Japan will never be the same.

Grandmother relinquishes control of the nation of Japan, which now orbits Earth like a second moon... ...and, during the battle, Tohru's wife, Kayuzo, acquires an alien battle-armor suit, making her nearly as powerful as Rai!

Later, during the Unity conflict, Mothergod causes Japan to fall from orbit, effectively destroying the once-proud country. Tohru attempts to avenge his slain countrymen, but is himself killed by the murderous Mothergod. Later, with Earth under attack by the evil Malev robots, Geomancer Rokland Tate infuses Takao Konishi with the fabled "Blood of Heroes", dubbing Takao as the "Last Rai". Now Takao wields the powers of the nanite-laced blood that once coursed through Bloodshot's veins. With the cry of "Mindlock!", he can mentally control the Malev invaders, one at a time. And Takao has a further talent. He has the Harbinger ability to psionically inspire others.

The stronger his own convictions are, the more others will be inspired to follow him. Fighting alongside this new Rai are Magnus, Tekla, the Eternal Warrior, Kayuzo in her X-O Commando armor, and the mysterious Spylocke. Rai's Mindlock power makes him the greatest threat to the Malev Emperor, and therefore he is a primary target of the evil robots.

Rai's campaign against the Malev invaders will take him around the globe. From Australia to South Am, Rai's struggle is as worldwide as his hopes. and what of the mysterious Spylocke? Is he truly an ally, or has he some private agenda? [source]