Complex sentence: His first novel "E. G. Combat" in 1998 was followed by science fiction and light novel works with his unique storytelling technique, which made Akiyama famous by his light novel series "Iriya no Sora, UFO no Natsu".
Split into simpler sentences: His first novel, "E. G. Combat", published in 1998, was followed by science fiction and light novel works. Akiyama became famous for his unique storytelling in the series "Iriya no Sora, UFO no Natsu".