With Fidel Castro's passing, Raul Castro's declaration that he will leave office on Feb. 24, 2018, and the irreversible march of time, Cuba is expected to be led by someone who did not fight in the Cuban Revolution.

In fact, the current heir apparent wasn't even born when the Castros and their comrades in arms seized power.

Raul Castro made international headlines in 2013 when he announced a successor in Miguel Diaz-Canel, then a little-known Cuban Communist Party functionary who had steadily climbed the ranks in government while many other prominent proteges of the Castro brothers rose faster only to be sacked from their posts.

When Raul Castro accepted a new five-year term as Cuban president, he said it would be his last and replaced his top lieutenant, Jose Ramon Machado Venturo, with Diaz-Canel, now 56.

Other potential successors had been identified by Cuban officials in the past, but they'd all been subsequently fired by the Castros.

The selection of Diaz-Canel, a relatively young leader, was the first time either Castro officially named a successor.

Raul said in February 2013 that Diaz-Canel's elevation to Cuba's first vice president represented a “definitive step in the configuration of the future leadership of the nation through the gradual and orderly transfer of key roles to new generations.”

For many international watchers, the announcement was a tectonic shift for the Caribbean's largest nation, because the Castros for years limited the inner circle of leadership to those revolutionary comrades, like Machado, who had helped them overthrow the Batista regime in 1959.

And if Diaz-Canel does become president, what does that really mean in a Marxist dictatorship run by the military and the Communist Party?

“When Raul Castro is the president, then yes, the president runs Cuba,” said Jaime Suchliki, director of the University of Miami's Institute for Cuban and Cuban-American Studies. “When Raul Castro is not president, that will be a very different matter. Diaz-Canel has no tanks and no troops.”

Still, the switch to Diaz-Canel will mark a transformation of its own.

One reason is that Diaz-Canel is at least 30 years younger than many in Cuba's ruling class; what's more, he is a civilian, not a soldier. How Diaz-Canel interacts with the military and other major institutions may show “how deep the continuation of reforms will be,” said Arturo Lopez-Levy, a native Cuban and researcher at the University of Denver.

Diaz-Canel trained to be an electronics engineer, but began working for the Communist Party of Cuba in 1993. In 2003, he was elected to the Politburo, the party's executive body. He steadily climbed the ranks.

Over the past few years, Raul Castro has given him high-profile duties.

Some foreign leaders have been visibly impressed with Diaz-Canel. “He's like a modern guy in the context he's living. He represents the face of change in the party,” said former Haitian Prime Minister Laurent Lamothe, who has met Diaz-Canel several times. “He used BlackBerrys to communicate. When you talk to him you can feel he is the future in Cuba, and he does have the backing and support of some of the most important people I have met in the Cuban government.”

If Diaz-Canel does become Cuba's leader, even his most optimistic supporters do not expect him to strike a radically different course for Cuba.

“Will he move toward the market economy? I would say yes,” said Lopez Levy. “Will he dismantle the one-party system? I don't think so. Everyone knows that a political opening in the current context is suicide.”

News services contributed.