Ken Takagi/Synopsis

History
Ken married a woman four years younger than him. They have a son who Ken is very protective of.

Shie Hassaikai Arc
Ken attends a meeting regarding the Shie Hassaikai, held by Sir Nighteye. He is confused about the presence of the U.A. High School students, as he deems them unfit to be a part of the discussion and incapable of contributing. When Tamaki Amajiki demonstrates that he can still use his Quirk despite being shot with the anti-Quirk drug, Ken states his relief.

When Sir Nighteye reveals that the anti-Quirk drugs have human blood cells in them and Eijiro Kirishima does not understand it right away, Ken points out that he knew the children would hold the discussion back. As Sir Nighteye further reveals that Overhaul's daughter is the one whose blood is used and that Izuku Midoriya and Mirio Togata already encountered them, Ken merely points out that the whole thing would be over with, if they had saved her right there.

With the main mission being the rescue of Eri, Ken asks if they know for certain where she is and points out that they might have removed her from the hide-out. After Sir Nighteye explains how his quirk works and that he can't prevent what he sees, using death as an example, Rock Lock challenges him and tells him he'll avoid his prediction a hundred times, only for Sir Nighteye to tell him that he cannot.

Ken later scouts out the urban environment to finds the Shie Hassaikai's hideouts. Later, when it is confirmed that Eri is in their hideout, Ken criticizes Sir Nighteye for wasting his daily turn of his Foresight, on checking out a villain who was buying a toy for Eri.

At the day of the mission, at 8:30am, Ken and several other heroes and police units gathered in front of the villain hideout. As the police officer asks them to do everything as smooth as possible, Ken is getting impatient and feels like the officer does not trust them. He then explains how the Yakuza are cowards and will probably not put up a big fight. When the heroes and the police are being attacked, he is surprised that they are not scared at all and put up a fight.

Ken along with the heroes and police make their way to the underground labyrinth to arrest Kai, they find a dead-end. Mirio phases through the wall and reports that the hallway is on the other side. After Izuku and Eijiro break through, Joi Irinaka begins twisting the hallway and closes off the basement's entrance. The heroes than fall down into a separate section of the building where they meet three members of the Eight Bullets. Tamaki decides to deal with the three enemies and tells the rest of the heroes to go on.

As the heroes went on they are apprehended by more of the Eight Bullets, Fat Gum and Eijiro are then separated from the group and face off against Kendo Rappa and Tengai. As Izuku, Shota and Rock Lock proceed to go after Kai, they are attacked by Mimic with his ability to manipulate the corridors, forcing Ken to use his super Move Deadbolt to prevent Mimic from continuing to manipulate the walls. Faced with this setback, Mimic changes his strategy and brings up walls from the floor that split Nighteye's team in three, leaving Lock Rock alone.

While Twice ambushes Sir Nighteye, Rock Lock is attacked by surprise by Himiko Toga. Rock Lock intercepts her knife with his hand, and strikes Himiko, but is surprised that the real Himiko has grappled him, revealing that the Himiko he struck was a clone made by Twice. Himiko knocks him out of combat after stabbing him and reveals that she's Himiko the gangster now, and not with the League of Villains.

Himiko drinks his blood to transform him and set a trap for Shota and Izuku, but Shota manages to discover the trap, forcing Himiko to escape. Twice is also forced to run away after being defeated by Nighteye, and later Joi is defeated by the heroes. The Police Force stood on guard preparing for Himiko and Twice in case they returned, while the detective declared that they could not ignore them.

As Shota tried deciding on the best course of action, Ken told them to leave the League of Villains to the Police Force and rescue Eri. The Police Force agreed on Ken's plan; Ken volunteered to stay and keep Joi in check since he was in no condition to move around. Ken reminded them of everyone else who was buying time for them and told them not to waste it. Sir Nighteye, Izuku, and Shota immediately headed out while Izuku promised Ken to rescue Eri.

Ken thought back to the meeting and noted that he had not been putting down the U.A. High School students. In actual fact, similar to how he cares for his newborn child, Ken was concerned for the safety of the U.A. students because at the end of the day, a child is still just a child. But after seeing them in action, Ken was relieved to know that the U.A. students were fine enough Heroes that put them to shame. Ken decided to hold Izuku to his promise and that Sir Nighteye take responsibility.

After the mission was a success, Ken was sent to the hospital. He was fortunate that Himiko's blade missed his internal organs and has recovered. Ken has to comfort his wife when she visits him with their son while recovering from his injuries.

Pro Hero Arc
Ken and Fat Gum attend the Hero Billboard Chart JP, where Japan top ten heroes are introduced since the retirement of All Might. He later comments on Hawks' arrogance after his speech.

Paranormal Liberation War Arc
By the end of March, thanks to the police investigations, and the information leaked by Hawks, who was acting as a spy, the Hero Public Safety Commission organize the Heroes and the Police Force to take down the Paranormal Liberation Front. Rock Lock is part of the team of heroes led by Endeavor in charge of raiding on Jaku General Hospital.

Before the raid started, Rock Lock participates with other heroes in a meeting where Detective Naomasa informs them about Dr. Kyudai Garaki, the current board chairman of Jaku General Hospital. He is an ally of Tomura Shigaraki and the creator of the Nomu, and that there is a section of the hospital that only he can access.

The raid begins, and the heroes quickly encounter Dr. Garaki in the corridors of the hospital. The heroes catch him before he can run away, but it turns out not to be the real doctor, but a clone created with Double. The real Garaki is in his secret lab and releases a horde of Nomu to fight the heroes as he tries to wake up Tomura from his stasis.

The Hospital becomes a battlefield, and Rock Lock is forced to fight alongside his fellow heroes to defeat the creatures. Little by little the Nomu are being defeated and the heroes begin to storm the Garaki laboratories, where they face various High-End Nomus. Rock Lock and other heroes use their abilities to restrain the High-End Woman, allowing Endeavor to land a finishing blow that destroy her head instantly.

All Nomu are defeated and during the confrontation, the capsule that contained Tomura is destroyed before Kyodai could reactivate his heart. Facing his defeat, a heartbroken Dr. Garaki declares that the Devil's Dream has finally ended.

However, against all odds, Tomura Shigaraki awakens, despite having previously verified that his heart was not beating. Seeing the situation, he immediately uses his decay, which spreads rapidly through the laboratory, disintegrating everything in its path. When the laboratory begins to crumble, Rock Lock manages to get on Ryukyu's back when she is in her dragon form. She manages to get him out of there along with a few heroes, before the entire hospital is destroyed, and the decay spreads to the nearby city, killing dozens of heroes on its way.