"The Onslaught of War" 「凶蟲無惨 Kyoōchū muzan」 is the third episode of Basilisk.
The episode begins with a palanquin being carried along a path by two men, with Jūbei Jimushi concealed inside. Meanwhile the Iga prepare to make their move, though Tenzen sends Jingorō back to Iga before they leave, telling him to keep an eye on Gennosuke. Jingorō grudgingly agrees and the group sets off, soon coming across Jimushi's palanquin. Koshirō kills the carriers and Rōsai removes the top, revealing Jimushi to the shocked Iga. Tenzen assures the group he can kill Jimushi alone and orders them to track down Shōgen alone. Tenzen begins to interrogate Jimushi but is caught off-guard when he attacks with a knife concealed in his throat and is killed instantly. Jimushi then continues his search for Shōgen and Danjou.
Elsewhere Oboro, Gennosuke, Akeginu and Jōsuke are seen walking down a mountainside on their way back to Iga. Oboro plays with the shadows on the wall, making it seem she is holding Gennosuke's hand. He notices this and turns to take her hand, cheering Oboro immensely. Jōsuke tries to convince Akeginu to do the same and jumps at her, but she swiftly dodges and he rolls off down the mountain. Later at night the Iga group ambush Shougen but, due to their recklessness, Nenki, Koshirō and Rōsai find themselves caught in Shōgen's web. Shōgen brags about his accomplishment and relishes in his victory, giving Hotarubi plenty of time to summon a swarm of butterflies. With Shōgen distracted she throws Koshirō's scythe to Nenki, who uses his hair to impale Shōgen in the head. As he falls Shōgen throws the scroll to a nearby Jimushi, who speeds off with it, followed but Nenki, Koshirō and Rōsai. Hotarubi tries to find out about Yashamaru but Shōgen refuses to answer and, in a fit of rage, she violently stabs him to death.
Deeper in the woods the three Iga are unable to catch Jimushi and, just when he thinks he can escape, his path is blocked by Tenzen. Confused Jimushi jumps to attack the man in his way but he is swiftly cut in two. The group then light a fire and, upon learning of Shōgen's status from the recently returned Hotarubi, burn the spare copy of the scroll. They then set their sights on attacking Manjidani themselves. Elsewhere, Oboro et all have arrived at Tsubagakure and are greeted by an unwelcoming Jingorō. The group enters into Tsubagakure but Gennosuke notices that Ogen's hawk is staring at him intently.