Adolfo Celi is the villain who cannot be bothered to threaten you. In Thunderball and the films around it he sits still, lets other men shout and looks faintly bored by his own wickedness, and it kept him cast as the heavy for years.
Fi1m perspective
In Thunderball (1965) a man is fed to sharks on Emilio Largo's orders, and Largo goes back to his lunch. That is most of Adolfo Celi's method. He wears an eyepatch, keeps his hands still and lets everyone else in the frame do the moving. Other Bond villains explain themselves at length; Largo barely bothers. Celi said his character had "everything, beautiful women, fast cars, high stake gambling, all of which bored him", and the boredom is what he plays. We found, watching it again, that the lunch frightened us more than the sharks. A man who can eat after that is the one to worry about, and Celi lets us reach that thought without help.
He did much of it without his own voice. His Sicilian accent was thick enough that he was dubbed in most of his films, Italian ones included, so what he had to work with was the body, the face and the pause. The career that used them started late. After training in Rome and a few post-war Italian films he left for Brazil in 1948, co-founded the Teatro Brasileiro de Comédia and spent about fifteen years there as a stage actor and director. He came back to Europe around 1964, played the villain in That Man from Rio (1964), and within a year was Battaglia opposite Frank Sinatra in Von Ryan's Express (1965) and Largo. Danger: Diabolik (1968), for Mario Bava, gave him one more heavy, Ralph Valmont.
The trouble with being that good at one thing is that people keep asking for it. Celi was cast as the heavy for the rest of his international career, and even in Thunderball he is outdone: Luciana Paluzzi's Fiona Volpe gets the sharper lines, and Connery wakes up for her, not for him. Celi's answer was to go home. Through the 1970s and 1980s he worked steadily in Italian film and television, three films with Mario Monicelli and two with Vittorio Gassman among them, and as Professor Sassaroli in My Friends (1975) he turned the villain's authority into comedy: the same weight, the same refusal to hurry, now aimed at a joke. When he did use his own voice, in the BBC serial The Borgias (1981), the accent was held against him, which is a hard thing to say of an actor who had spent his international career proving he did not need it.
Start with Largo, because everyone does, and watch what Celi does while Connery is talking. Nothing, mostly, and it is harder than it looks. Then find the Italian comedies, where the same stillness is turned on the people around him for laughs.
Biography
Adolfo Celi (27 July 1922 – 19 February 1986) was an Italian actor and director. He is best known internationally for playing Emilio Largo in the James Bond film Thunderball (1965).
Born in Curcuraci, Messina, Sicily, Celi appeared in nearly 100 films, often in supporting roles as villains. He began his career in post-war Italian cinema and spent many years as a stage actor and director in Brazil and Argentina, co-founding the Teatro Brasileiro de Comédia and directing three films there, including Tico-Tico no Fubá (1952). His other notable film roles include appearances in That Man from Rio (1964), Von Ryan's Express (1965), Danger: Diabolik (1968) and My Friends (1975).

