Babylon

Babylon is the Goddess who resides in the Holy Grail that was in Demon King’s Labyrinth.

Appearance
Babylon appears to be a middle school student wearing her uniform. Her figure is small and can fit in the palm of Horn's hand which is the size of a child.

Personality
Babylon is a playful sort, very bright and bubbly. She likes to provoke Horn, has an adventurous spirit, and often withholds information that is valuable to Horn, which causes her problems. She acts like a spectator, but Horn makes use of the fact that she is the only one who can see her and hear her, to force her to work in her favor about threatening to damage the Holy Grail.

Abilities
She has the power to level someone up if they offer blood to fill the Holy Grail.

She can sense objects that can level someone up.

She threatened to curse Horn several times. Whether if she has that power or it is an empty threat has yet to be proven.

Horn
She offered blood (in fact it was urine) to the holy grail, and as a result, she is the only one who can see and hear Babylon.

Trivia

 * It can only be seen and heard by someone who has offered blood to the Holy Grail, the blood offered will be consumed by Babylon which will convert it into Level Up.
 * Horn offered no blood, but during her intrusion into Diablo's labyrinth, she used it as a toilet to urinate, which Babylon confused with blood, though she herself claimed that it tasted strange.