An armed police officer or escort. See https://en.wikipedia.org/wiki/Kavass.
The graph displays the other subjects mentioned on the same pages as the subject "Cavass". If the same subject occurs on a page with "Cavass" more than once, it appears closer to "Cavass" on the graph, and is colored in a darker shade. The closer a subject is to the center, the more "related" the subjects are.