Six is Kin, a deeply rare Fey-Darkness crossover. She is a trained assassin, one of the Darkling Twelve who serve under the Raven KingSee Kanon. . Influential in Notte’s life, she taught NotteName meaning: Night (Italian - he picked that one) Other ... self-defense and assassination during his time in the city of Az’KabekOne of the most important cities of Notte's youth and the la... .
Also, incidentally, Six is based off a wonderful reader: Sixelona.