Ghosts Return

Ashura, as most know him, lives pretty much simplistic life for an immortal. He lives in a huge mansion with his girlfriend Platina. However as an immortal is important to take care of their own health.
As of one night, though, Ashura leaves his home for an usual night stroll. Unfortunately, he mysteriously overheats during the cool night and eventually faints. All he could see before blacking out completely are few paramedics taking him to the nearest hospital. However once he wakes up he finds himself in abandoned emergency room .
After this terrifying experience he constantly sees and hears malicious entities, some even daring to hurt his family. No one else sees them tough, which makes the situation harder to explain. Is it simply the traumatic event that causes these apparitions or there are really ghosts its up to find out further in the story...