Serenity

Serenity Aleister is the protagonist of the game and the wielder of the Demons' Score. She's an average girl enrolled in Boston College. An email from he father Dr. Aleister prompts her travel to Salam, Massachusetts to pay a visit to the research hospital where he works.

When Serenity arrives at the hospital, she finds it barren until she meets David, a talking teddy bear. The two are then attacked by a demon, to which Serenity kills with gun David gives her. Worried about her father, Serenity runs deeper into the hospital with David following close behind.

Along the way, Serenity discovers that she can use magic to flying through the halls. With David's tutelage, she manages to master her weapons and advance farther into the asylum.

Soon they come across an archfiend named Asmodeus. With determination, Serenity is able to defeat the demon. Serenity then discovered that the cell-phone around her neck contains an app for a program called "Demons' Score" which allows the user to summon demons. David claims this app was created by Aleister.

Going through the sewage system has the duo run into Belial. Defeating him adds his soul to the Demons' Score, which begins to incombers Serenity. David lets it slip that Dr. Aleister was testing opening portals to Hell, which surprises Serenity. However, David brushes off her concern and leads her deeper into the hospital.

In the courtyard, they meet a demon lord named Eligos who is also researching demonic scores. After defeating him David reveals that he approached Dr. Aleister with a book that contained musical scores composed by a demon. The doctor was helping him decode the book when he was suddenly blasted out of his body and into a teddy bear. Leaving it at that, they press on.

Arriving in the medical wing, Serenity discovers a bed with her name on it and is taken aback. Soon they meet Lilith who halts there advance. Once she's defeated, the two spot the gateway to Hell opening, and they hurry to it. They are then obstructed by Astaroth, who seem to recognize David. On the verge of defeat, Serenity unlocks a new power from the Demons' Score and overpowers Astaroth.

Serenity suddenly receives a message from her father that repeats "Remember." And Serenity begins to recognize the hospital as the place she was born. Finally, they reach the portal which is guarded by Satan. While fighting the demon, it's shell opens to reveal Dr. Aleister partially fuse with the fiend. Serenity's father begs her to kill him along with the monster and says his goodbyes before Satan is fully awoken. Serenity hesitates and is leaves herself open to the demon's blast. At the last moment, David jumps in front of the blast and his body is destroyed. His selfless act triggers Serenity's final form which allows her to defeat Satan.

With the Demons' Score completely upgraded, Aleister emerges from Serenity's phone. David returns and tells her that Aleister was to become a god and she is the doctor's experiment, meant to be his messiah. David gives her a choice to either follow her father's plan or make her own destiny. Serenity raises her sword and strikes down Aleister and choose to set her own course.