Whisper

Whisper (ウィスパー, Uispā) is the spirit of a human who died of hunger residing at the Haunted House. He cannot enter the afterlife due to the memories of his life being incomplete, and thus asks the Protagonist to help him.

Releasing Hager and Corralling Tone Souls
After setting off the alarm on Dr. Hager's machine in the left hallway and subsequently saving him in the cellar, Whisper will be on the first floor with the "tone souls" which must be herded into the clock at the top-right. Afterwards, Whisper will invite the Protagonist to the room at the end of the right hallway, where he will talk about his lost memories and the painting on the first floor.

Hint
Once you check the painting (at the top of the staircase to the 2nd floor, you have to stare at it for a while and then walk away), you will be asked to find 3 different food items, one at a time. The first two can be found in or near Castle Town. The third is more difficult to figure out, and is something you cannot get until you help the Kakunte in the Mushroom Forest and bring Tottoteruri's soul back to its body (make sure to talk to a particular Kakunte who will show you a hidden area, once this is done).