The Real Kei Nagai 1 is the 10th chapter of Ajin: Demi-Human, created by Gamon Sakurai.
The chapter begins with Sato noting Kei's strange behaviour after being unaffected by his killing of the guards pointing out that guarding the place was their job and that they were already dead. Sato thinks about his behaviour up until now and thinks that, while he did declare him as a failure, he should still observe him for a little while longer.
Ikuya continues explaining that IBM are a physical being. When questioned with why they were unable to see it Ogura shows off his middle finger explains that light reflected off his finger allows their eyes to perceive it. Ogura goes on explains that glass is transparent because glass is made up of a substance that allows around 80-90% of transmit through it, where as IBM's allow 100% of light to transmit through. Kishi quickly dismisses all of Ogura's claim as crazy and he shouldn't be so proud that he was acknowledged by a crude country such as America. Ogura retorts by pointing out that it was Kishi's thickheadedness that stopped them from reaching the next stage.
Sato is holding three surgeons at gun point who were trying to surrender before quickly killing one of them. Before he has a chance to kill the rest Kei stops him pointing out that they were surrendering and that they could crush their arms and legs instead. Sato laments on how Kei was truly a failure and lets go of his gun and pulls out a pistol to shoot Kei with, however before he had a chance to do so Kei shoots Sato with the gun he just let go. Seemingly angry Sato promises to kill Kei along with the surgeons. Kei quickly realises that Sato's motto of living a peaceful life was a lie and that escaping has just become a lot harder.
While Kei hides with the surgeons he suggested that he'll act as decoy while the surgeons show him the safest route outside. Sato calls out to Kei informing him that Ajins are capable of dying, explaining that if he chopped of Kei's head a new head would be generated in its place while the old Kei would die. Even though he was shaken up Kei was still determined to escape.
Sato spots three fingers sticking out next to a cabinet he prepares to attack Kei only to realise that the fingers had been cut off. While Sato was distracted Kei attacks from above with a knife aiming for his spine.