Sword Art Online, Vol. 20 (light novel)

The Taboo Index and the Law of Power have both been breached by a singlemurder. The shadowy culprit's intentions are clear as day: the human realm andthe dark territory must go to war again. With the help of Iskahn, commander ofthe Dark Army, Kirito seeks to bring the criminal to justice. But as theyconduct an investigation with Asuna's help, disaster strikes again! Ronie andTiese have been poisoned!