Six Great Treasures

Hiragumo

 * Talk to Inukai at 7 Trust to initiate the Flat Spider Event.
 * Finish the Flat Spider Event, to do so you have to find 蜘蛛弾正 (Gumo Danjo), who is a random archer grunt, and send Inukai for that battle out and destroy the grunts unit. After the battle, Inukai will kill Gumo Danjo and you will get the Flat Spider(Hiragumo),