At nChain, Dr. Wright was a difficult boss, prone to shouting, four people who worked with him said. He liked to flaunt his wealth, bragging that he had more money than the entire country of Rwanda. Employees at nChain attended extravagant parties in London: At one memorable event, arranged by Mr. Ayre, guests ate sushi off the bodies of naked women, while performers in samurai costumes hovered nearby, two of the people said.