Babylon is the Type Guardian Embryo belonging to Rook Holmes.

She has a warm and friendly personality that can easily get along with most people. She cares deeply for Rook and comforts him whenever he is feeling down.

As a Type Guardian Embryo, she is capable of operating independently from Rook. Due to her ability to absorb a large number of skills, Babylon's status is below the average for a Guardian.

(Source: Infinite Dendrogram Wiki)