Fifth Pillar arc

The Fifth Pillar arc is the ninth story arc of the Fire Force manga series. Focusing on the awakening of another user of the Adolla Burst and Adolla Link. The strangely empowered Inka finds herself caught between Special Fire Force Company 8 and the Ash Flame Chivalric Order. With Shinra Kusakabe coming into conflict with Charon and Company 8 attempting prevent an Infernal Outbreak.

Danger Begins
After a successful outing, extorting an old man in exchange for saving his life, Inka, Panda and Sancho divide up their earnings. The three 'fire thieves' also discuss Inka's strange ability to predict fires through her sense of smell, which Inka claims is a sign she is part of the Fourth Generation. While discussing her desire to live dangerously, Inka briefly sees the ghostly Hitohashira Me, who warns Inka that a danger so great in will make Inka fall in love. Meanwhile, Captain Akitaru and Shinra discuss the possibility of another user of the Adolla Burst appearing and Hitohashira Me tells Shinra that the 'Fifth Pillar' is about to be born.

Inka looks upon Tokyo and sees that many fires are going to break out across the city. As these fires being, a number of Infernals appear as well. Resulting in Company 8 mobilising. While traveling in the Matchbox, the Company discusses Inka's reputation and bizarre power, coming to the conclusion that she might be the new user of the Adolla. Company 8 use Maki's Iron Owls to scan the area from above and see both the spread of the flames and the number of Infernals. With a minimum of 8 Infernals, Akitaru concludes that the Ash Flame Chivalric Order are using the Bugs in order to create this disaster. As a result, Company 8 spread out to control the situation to the best of their abilities. While the majority of the Company aid the evacuation and destroy the Infernals, Shinra is sent to find Inka and the White Hoods while Arthur is sent deal with Haumea if she appears.

Akitaru's suspicions are justified as Haumea is within the chaos. Using her electrical signals to locate Inka in a nearby park and directs Charon and his men towards their target. Sancho and Panda's attempts to stop Inka from endangering herself are interrupted by Charon appearing behind them. During his attempt to convince Inka to leave with him, Charon responds to Sancho grabbing his shoulder by blasting a hole through his chest. In the stress of seeing her ally die in front of her, Inka's abilities begins to evolve. Allowing her to create explosions around Charon, creating an opportunity for her to lure her attacker away from Panda by escaping into the city.

Inka is backed into a conner by Charon and his men, only for Shinra to strike from above. Landing between the blindfolded zealot and the fire thief, Shinra promises the confused Inka that he will protect her. Inka views his statement with scepticism and contempt as Charon engages Shinra in combat. While Shirna's attack barely phase Charon, Charon's strikes prove to be utterly devastating to the Fire Soldier. Eventually, Inka chooses to view both fighters as her opposition and unleases a mass of chaotic explosions to flee from them. Shinra moves to give chase, only for Charon to focus on him. Charon sends two of his followers after Inka while he and the rest move to capture Shinra, who has been declared the 'Fourth Piller' and is deemed necessary for the Preacher's plan.

Containing the Outbreak
While Akitaru has manages to defeat 3 Infernals, Vulcan confirms that their numbers are rapidly growing as the result of the White Hood's attempts to find a new host of the Adolla through the Bugs. The battle escalates, forcing Vulcan can defend himself from a surprise attack and pushes Hinawa into shooting the Infernal before Sister Iris can recite the traditional prayer. Maki is able to spot Haumea on a nearby rooftop and directs Arthur towards his target.

Hinawa and Vulcan move through the streets to confront a mass of Infernals, only to be confronted by a Demon. Vulcan calls for assistance but Akitaru and Iris are too far away. As a result, Tamaki appears dressed as a nun in order to recite the prayers and Karim from Company 1 arrives to aid them further. He does this by freezing the hoard of Infernals using his Thermoacoustic Refrigeration. Shinra receives help from Company 5's Tōru Kishiri and Company 2's Takeru Noto, who free him from the White Hood's grasp and allow him to chase after Inka. Shinra's flight is interrupted when Charon grabs him out of the air and slams he through a wall. The two struggle and Shinra is able to knock Charon through another wall and onto another rooftop. Before they can reengage, Shinra looks down and sees Inka struggling against the agents holding her down and refuses Shinra's help.

Akitaru and Iris make contact with members of Companies 1, 2 and 5. Meanwhile Arthur begins to battle against Haumea. This causes Haumea to order Charon to move quickly so they can escape. During her battle with Arthur, Haumea reveals there are meant to be Eight Pillars of the Adolla Burst that the White Hoods are trying to control.

Charon knocks Shinra down into the street and continuing their fight. With his high-speed attacks failing to work, Shinra decides to attempt to create an explosive attack using the Sing of Horns. In an attempt to understand what Charon's ability is, Shinra examines his style of counter attacks and realises that Charon is actually a member of the Second Generation. This ability allows Charon to harmlessly absorb kinetic energy and release it as explosive force. Shinra initially attempts to avoid hitting Charon, but the martial artist orders his followers to beat him until he has enough energy to produce a blast that brings Shinra to his knees. While collapsing, Shinra realises that Charon cannot release and absorb energy at the same time: meaning he is briefly vulnerable to a counter attack. With this knowledge, Reinvigorated, Shinra engages Charon for the final time and after multiple failed attempts combines his Rapid with the Sign of the Horn to blast Charon skywards with Hellfire.