Denny Walden was the biology teacher of Leafmore High. He appears several times; sometimes offering help, other times obstructing the main characters in a frantic manner. The player later discovers this is due to him recently obtaining knowledge of his employer's actions.
He was a critical part of the Incident since because of him, the monsters overran the school. Prior to the events of ObsCure Walden came across Friedman's secret laboratory under the school and somehow became infected which may have been caused by exposure to the mortifilia spores, creatures, or Friedman himself. However he managed to escape but left the lab open in the process resulting in many of the creatures escaping. After this event Walden tried to keep his composure for the sake of his students, but as the spores spread within his body it put great strain on his sanity. He is also the teacher of Josh, Kenny, Shannon, Stan, and Ashley.
Walden first appears just after the prologue teaching a biology class which Josh, Shannon and Ashley are attending. He seems to notice the group discussing Kenny and tells Josh to sit down who quickly complies. He is next seen saving the trio from some monsters by smashing the back window and letting the light Kill them. He appears Injured which Shannon makes a note of causing him to act defensive while keeping out of the light. Walden is not seen again until Josh and Stan are investigating the file storage in the teachers lounge. He appears more paranoid and confused as he is looking for Friedman in a drawer which Stan pokes fun at. He helps them by giving them a key to the auditorium against his better judgement before leaving to continiue his search. He makes his next appearence after the group are finished in Friedman's hidden office and have found a map of the underground lab. The infection appeared to have taken hold in full as his appearence has become warped and sharp and he begins vomiting dark blood. He then steals the map and locks the group in the infested library. Walden then makes his way to the big door where Leonard Friedman is located in hopes of finding a cure for his condition only to be confronted By Herbert once the door opens.
Walden confronts Friedman in his lab with a gun not knowing that the monstrous form of Leonard is watching the exchange. Friedman tries to bring Walden to his senses by expressing sympathy and telling him that the cure isn't guaranteed to work for him do to his exposure to the sun and his current state of mutation. Unfortunately the former teachers mind had snapped and despite Friedman's warnings shot the headmaster down. Walden then proceeeds to take the case containing the incomplete cure and injects himself with it in the hopes of curing himself. Is unknown is the cure work, because a enraged Leonard impales the teacher on the end of one of his barbed tentacles for killing his twin, before finally killing him by slamming him hard enough into the ground to shatter his skull leaving his slumped body by the door to the horror of Ashley and Kenny who have just arrived at the scene with the other students. In a way Walden helps the teens by leaving them enough ammo to kill Leonard.
- Walden could have been the one who killed Nurse Wickson by brutally beating her to death. No monsters could have gotten to her due to the lights having been turned on prior to her death. This could have been a desperate attempt to get information about the cure.
- It is unknown how he was infected but it was more likely from one of the creatures due to Friedman's desperate attempt to convince him that the cure would not work for him. Friedman also seemed to not know that Walden was infected although he did know that he had been in the lab.