Nataku Son

, also called by friends, is a child residing in Tokyo. After being forcibly bitten by the Bug, he adapted to the flames and became a Third Generation. Haijima Industries then took him in, with scientists performing experiments on him, which eventually leads to his awakening of the Adolla Burst, and becoming the Sixth Pillar.

Appearance
Nataku is a young child with light-blonde, short wavy hair and light eyes with small black pupils. He dons a light a v-neck sweater, a black shirt, black trousers, and black shoes. After his awakening, his pupils turn white and he wears a lightly-coloured fire-proof coat with a lengthy sleeve on his right arm, which completely obscures his limb. The right sleeve of his shirt is cut short while the left sleeve reaches down to his wrist. His hair also seems to have lengthened somewhat since his first appearance, appearing as a small flame.

Personality
Nataku is a straight-forward and kind boy who wishes to help people and to be strong. He showed bravery in trying to stop Rekka Hoshimiya from turning innocent people into Infernals. However, Nataku suffers from a debilitating sense of anxiety caused by always trying to do the right thing and live up to the standards of other people. This means that he has a deep fear of failure and cannot admit to being incapable of doing as he's told, be it studying to become a doctor or violent training exercises. These concerns have become substantially worse as he has shown signs of Post-Traumatic Stress Disorder following the Rekka encounter. Nataku hallucinates that Hoshimiya is encouraging him to act and become more powerful, which gives him more determination to succeed while also putting him under more pressure to succeed. In reality, Nataku just wants to be allowed to accept his limits and to be allowed to be weaker.

Abilities
After being bitten by a Bug, Nataku developed Third Generation abilities. Due to his age and lack of experience, he is currently unable to fully control his abilities. Using his Ignition Ability, he can ignite a claw from his right arm. As the Sixth Pillar, Nataku possesses the Adolla Burst and is able to forge an Adolla Link with others using emotions such as desperation and fear. When his Adolla Burst fully manifests, Nataku becomes able to create floating radiation symbols out of fire, which are able to fire beams over great distances and cut through concrete. Nataku also begins to emit radioactive energy that is dangerous to everyone in his immediate area unless they have a resistance to fire. It is believed that Nataku's uncontrolled power could destroy the entire Tokyo Empire.

VS. Special Fire Force Company 1 Arc
While walking with his friend, Nataku was confronted by Tamaki Kotatsu in the streets and was carried off to an abandoned warehouse, being told that there was a way for children to be immune to the phenomenon, he followed. At the arrival, Nataku was frightened to see Rekka turn, someone, into an Infernal, and he himself, was bitten by the Bug and began the transformation into an Infernal. However, Nataku seemed to be compatible with the flames and did not transform into an Infernal, simply passing out without injury. Before he can be taken by Rekka, he is protected by Shinra, Tamaki, and the other members of Company 1 as they battle and defeat Rekka. After the ordeal, he was taken in by Haijima Industries.

Hajima Industries Arc
As Company 8 begin their investigation into Hajima, Kurono Yūichirō prepares Nataku for their third combat test against each other and refuses to let him go home. As Shinra only revealed his Adolla Brust during actual combat, the scientists study Nataku's reaction to danger. In response to a hallucination of Rekka, Nataku unleashes his flames but is ultimately defeated.

Shinra and Victor Licht investigate the Hajima's complex and the scientists try to hide Nataku's location, but Shinra senses Nataku through the Adolla Link begging to go home, proving that he is there. During Shinra's battle with Kurono, Nataku's abilities fully awaken and causing havoc. Despite security guards and Shinra rushing to find him, Nataku is captured by Kurono who fights Shinra while carrying the boy by the neck. After reaching the courtyard, Kurono is attacked by Charon and loses hold of Nataku until he kills Charon's henchmen. Nataku is tossed around between the Fire Force, Charon, and Kurono until Ritsu manages to trap him within the body of her newly-formed Fire Giant.

Feeling deeply distressed over his current situation, Nataku also feelings inspired by the memories of Rekka and the puppeteer telling him to be hopeful. This mixed emotions combined with Haumea increasing his aggression causes Nataku to lash out everyone in the surrounding area. Firing beams at Kurono, the Fire Force, and the surrounding area; Nataku also begins creating radiation that begins to endanger everyone in the area. While Shinra and Charon work together to bring Nataku under control, he hears the voice of Rekka telling him to cause more destruction. Despite not being able to break through the giant's body, Shinra is able to forge an Adolla Link and see into Nataku's mind. Shinra tries to encourage the boy to stop being afraid. Nataku's fragile mental state interprets this as an instruction to unleash his full power on the city, releasing a colossal blast of radioactive energy. The city is saved from destruction by Charon reflecting the blast into the sky and out of the atmosphere.

Seeing how powerful the boy has become and what his desperation has brought him to, Kurono destroys the Flame Giant and rips Nataku out of its remains. Understanding that Nataku wants to accept his own limitations and weaknesses instead of living up to impossible standards, Kurono manages to calm Nataku down by telling him that he doesn't have to force himself to be powerful. Finally being freed from the pressure he's put himself under, Nataku calms down and the radiation dissipates. Following the incident, Nataku continues to be tested by Kurono but seems more at peace with himself and able to keep Rekka's influence under control.

Trivia

 * Nataku currently has white pupils like Shinra, Sho, and Inca after awakening his powers.
 * It is possible that 25 people were killed by Nataku's Infected Imagination Rampage. There were 6 killed by Kurono and 1 killed by Ritsu.