Ma'jhad Kha is a Khajiit residing in Steelheart Moorings, Stormhaven. He was a slave himself but turned on his masters and took over. He killed his competition and became some kind of slaver king. He is their leader now and has commandeered a house for his own.
Slavers are using Steelheart Moorings as their base of operations and they're holding some sailors who they recently captured. The first mate has asked the Vestige to help free the sailors from the slavers' clutches.