Sword Art Online Progressive 3 (light novel) — Reki Kawahara

After reaching the second floor of Aincrad, Asuna decided to have a player controlled blacksmith upgrade her beloved sword, a rare Wind Fleuret--but when the unimaginable happened and the sword was shattered in the attempt, Kirito suspected foul play. Did the blacksmith really just happen to destroy an incredibly valuable item? And if not, is there any way to get it back? And--if there really is a conspiracy of thieves--how can they be stopped before they spread too much mistrust? The game of death is bad enough already!