Killtacular is the ninth chapter of the manga Ajin: Demi-Human created by Gamon Sakurai.
The chapter starts with a crowd of people outside the Ajin Research Facility containing Kei, as well as several news crews which state that Ikuya Ogura's vehicle has just arrived and is entering the center. On the other side of the facility however, we see a murdered guard and a broken fence where Tanaka and Sato have broken in, carrying several heavy weapons with the intention of amassing more firepower than the enemy in order to roll over them, saying to Tanaka "No cute tricks, thank you".
Ogura then enters the facility as seen on a monitor being watched by Izumi, Tosaki and several other staff, with tosaki explaining that the Japan-US agreement isn't a cooperative one at all, and is only an official story fed to the public. He explains that it is in fact just a transfer of info between the two countries, but before he can elaborate further, the entire facility is shook by a massive explosion.
While everyone present questions the cause of the event, Tosaki is snapped back to reality when a member of the security team appears on the surveillance monitor, and informs him that a man wearing a hat has infiltrated the facility. When Tosaki realises that it's Sato, he questions why he would attempt to rescue Kei when he was the one who gave up on him. The security guard is killed however and Sato appears on the screen instead, saying that while they may not understand why he is there, "demi-human affairs in Japan are in for a sea change", before taking his leave.
The story shifts to a corridor with several other security guards armed with tranquilizer guns, all eyes trained on a door at the end of the hallway. Sato breaks through and a gun fight ensues, with Sato murdering all of the guards and proceeding to Kei's containment room.
While watching the massacre, one of the people with Tosaki states that his immortality isn't the issue, the real problem being his combat ability, before Ogura enters the room having escaped his vehicle before Tanaka could capture him. Ogura goes on to explain the Ajin's power in a somewhat crude manner, saying that the black ghosts are invisible to begin with, and are comprised out of an unseen matter.
Before he can go into anymore detail however, the story cuts back to Sato who has just broke into Kei's containment room. Breaking him free, Sato has a flashback to the time he first broke out Tanaka, remembering the look of anger on his face when he was freed from captivity. When he releases Kei however, he has a much more different reaction apologizing to Sato for the trouble he brought him and Sato regarding him as a "fail".