Javier Cortes (ハビエル・コルテス Habieru Korutesu)
, also known as the Locked Room Master (密室先生 Misshitsu sensei)
, is the mastermind behind fifteen locked room murders. Javier is a high school student living in La Palma
who wants to be a mystery novelist when he grows up. Tsukumojuku Kato
implies that Javier doesn't have what it takes to become a writer, as when Tsukumojuku, George
, and the police had burst into Javier's house, they found notebooks filled with locked room tricks but no actual novels.
Javier has a Wound that allows him to travel through anyone's dreams, similarly to the Stand Death Thirteen. Javier would wear clown clothes and makeup, enter the dreams of vulnerable victims, work his way into their hearts, and draw out their darkest emotions. Javier would first find someone his victim hated or had trouble getting along with, and then manipulate his victim to blame all their negative emotions on that person. He would twist their fears to make the victim think that person was the source of all their problems. Despite how forced the logic or reasoning was, Javier's target would believe him after his constant whispering to them in their dreams. He would go as far as to torture them if necessary, by either killing them in their dreams or having their enemy kill them. Javier's victims would awaken in a nervous frenzy and feel as if the real world was a dream. Eventually, Javier succeeds with fifteen victims and they murder their targets in locked rooms. As his victims do not remember the details of their dreams when they awaken, they assume they created the tricks for the locked room murders themselves.
Tsukumojuku assumes that Javier was abused and molested for over ten years by his mother, Leonora Cortes, which developed his Wound ability. Javier would comfort Leonora when his father, Juan Rovira Cortes would make her cry. Whenever Javier slept, he would be trapped in a locked room with his mother. Javier's desire to escape from his flesh while he was in that locked room with her manifested into letting him sleep and escape through dreams. He would get an unhealthy amount of sleep, as he was also sleeping during the day and entering the daydreams of his victims. Javier admits to George that the one he really wanted to kill was himself.
Javier ends up being caught by the police when he attempts to target Penelope de la Rosa, who has a pathological fear of clowns. Penelope clearly remembers her dreams but nobody believes her aside from Tsukumojuku and George. They bring up the dreams to Javier's other victims and they end up remembering him. Javier had talked a lot about himself in their dreams, as he was overconfident that they wouldn't remember him. From their descriptions, George and Tsukumojuku were able to piece together his identity and draw a composite sketch.
The Spanish police on La Palma beat Javier to death with their nightsticks and sink his body in the bottom of the sea at night. George and Tsukumojuku were powerless to stop them and Leonora didn't even try. If stories spread about Leonora's son being a witch because of his mysterious powers, the church would end up being involved, and Leonora's entire family would be persecuted.