Franz Sanchez was a drug lord who was captured at the beginning of License To Kill, but escaped with help from a traitor and had his revenge against the people who had him captured. James Bond then decided to have his revenge against Sanchez for Sanchez hurting and killing some of his friends.
Sanchez was one of the few villains in the Bond series who managed to actually badly injure or kill one of James Bond’s closest friends, his long time ally named Felix Leiter. He not only murdered Leiter’s wife, he also had Leiter partially eaten by a shark. Despite being a ruthless villain, he’s also pretty charismatic and loyal. He takes people who help him under his wing such as befriending James Bond when it looked like James Bond was trying to help him and paid off Killifer instead of having him killed showing he pays people back honestly for what they do for him. He was a good guy to have on your side, but serious trouble to go up against.