Who is Jacky's nemesis at the Lawson Peabody school in the novel, In the Belly of the Bloodhound?

Clarissa Worthington Howe is Jacky's nemesis at Lawson Peabody school. Clarissa is a spoiled rich girl from the South who has a slave named Angelique. Clarissa shows her bravery and cunning during their time in captivity.