Short answers, pulled from the story.
Yokoyama is credited with founding or pioneering several core manga and anime genres. These include mecha with Tetsujin 28-go, magical girl with Sally the Witch, ninja action with Iga no Kagemaru and Kamen no Ninja Akakage, battle manga with Babel II, and literary adaptation with Sangokushi.
Yokoyama died at 10:00 in the evening on the 15th of April 2004, aged 69. A fire broke out in his house that morning, leaving him with severe burns. He fell into a coma and died in a hospital near his home later that day.
Yokoyama established the structural format of many of manga's core genres, including mecha, magical girl, ninja action, and literary adaptation. While Osamu Tezuka had established the fundamental techniques for drawing Japanese comics, Yokoyama defined the formats that various genres took.
In 1991, Sangokushi won the prize for excellence from the Japan Cartoonist Association. An animated version of the series was also broadcast on TV Tokyo that same year. Sangokushi ran from 1971 to 1987, making it a sixteen-year project drawn from Chinese historical sources.
Otomo said that Akira has the 'same overall plot' as Yokoyama's Tetsujin 28-go. Four characters in Akira are identified by the numbers 25, 26, 27, and 28 as a direct homage to Yokoyama's title.
Araki said he was conscious of Yokoyama's hard-boiled style, specifically sticking to suspense and describing hero characters drily. He named Babel II as the origin of Jotaro Kujo wearing his school uniform in the desert in Stardust Crusaders. Araki also said that if he were to draw Stardust Crusaders again, he would base the Stands on Tetsujin 28-go.