Question: Which writer illustrated a Japanese Manga Series which spent 18 weeks at the top of the New York Times Manga Best Sellers list of 2009?
Sentence (from "The New York Times Manga Best Sellers of 2009"): ", 3 weeks; "Chibi Vampire", 1 week; "Fullmetal Alchemist", 1 week; and "Warriors: Ravenpaw's Path", 1 week.
Relevant evidence: No