Nightgale

In the underground city of Nightgale, invisible walls mysteriously appeared one day, blocking various parts of the city. Many people tried to go through them, and with a certain method, you could. At the same time as the walls coming up, a cloaked figure started killing anyone who passed through the walls, and a virus that turned people into murderous demons also found its way into the city.
As panic spread through the city of fear for turning into an Inflicted, the walls started shrinking, meaning almost certain doom. However, one day the walls stopped shrinking, but there were threats of it happening again. As the city turns to ruins, a teen and his friend try to solve the mysteries at hand. If he isn’t careful, he may not live to finish his task at hand.