Which of the following is a senior Byzantine court title that was introduced in the early 12th century?

There have been despots throughout history, of course. Pol Pot comes to mind immediately, a tin pot despot who murdered 1-2 million of his countrymen in the small country of Cambodia. There was also King Leopold II of Belgium, who staked a personal claim on the African country of Congo. In pursuit of rubber, he enslaved the whole native population. Every adult had a daily quota of work. If not met, they were severely beaten. Multiple failures to make quota resulted in having a hand chopped off. Combined with starvation and disease, one half the Congolese population died. Finally, world outcry led to the country of Belgium taking over the country. That's when it became the Belgian Congo.