It seems a bit ironic that Giancarlo Esposito and Michael Mando are appearing in the same franchise but are so far apart, in terms of release mainly. This had led some to believe that there's indeed a connection and that Far Cry 6 serves as a prequel to Far Cry 3, with young Diego being a younger Vaas. For many reasons, this doesn't seem true unless Ubi retcons a lot of lore, but nonetheless, the two villains are worth discussing.
After all, the Far Cry franchise puts more stock in its antagonists than it does the protagonists, as the likes of Pagan Min, Joseph Seed, and now Anton Castillo have to live up to Vaas' legacy. That does not mean Vaas' legacy could be mimic'd though, as based on the characterizations alone (since the sixth installment is not yet out), Far Cry 6's Anton Castillo is incredibly different from Vaas.
Far Cry 3: Vaas, a Hilarious and Murderous Psychopath
Vaas is perhaps the most iconic Far Cry villain, and one who many would agree has not yet be quite matched. Pagan Min was eccentric, not unlike Vaas. Joseph Seed was slightly over the edge, not unlike Vaas. But none could really establish their own character and follow in his formula. This could be one reason that Far Cry 6's Anton is almost the complete opposite of Vaas.
Their roles in the story couldn't be any different, as while Far Cry 3's Vaas was the dominant villain, he was not the primary antagonist. Hoyt has that role in the story, but Vaas was the main one and true archenemy of Jason. Vaas tormented Jason, making him rise up and become the warrior that he does. Many probably don't think much of Hoyt, but no one forgets Vaas.
After all, part of Vaas' charm was how his unpredictable nature and pure insanity. The game felt very much the same way, and the two reflected one another. Jason is forced to get mystical tattoos, climb out of a mass burial pit, hear Vaas' definition of insanity, burn down a marijuana farm, and so much more. At the end of the day, though, he still had to deal with Vaas.
As a character, Vaas had clearly turned his back on his sister and the Rakyat, having no real feelings for his family. His morals had degraded into insanity as well, as while Vaas was a murderer, he never really acted "evil." He had no moral compass, acting as he pleased and lashing out as he liked in Far Cry 3. All of this combined into a package that was as interesting as it was, at times, terrifying.
Far Cry 6: Anton, a Cold-Calculating Dictator
Anton, on the other hand, is much more different in so many ways. Anton does appear to be the primary villain of the Far Cry 6, yet his motives are not pure insanity or some notion about the end of the world. Anton knows he takes center stage, and with the acting chops of Giancarlo Esposito, he seems to make the most out of it. He is no one's second fiddle, even if he puts a lot of emphasis on Diego his son. It does remain to be seen how his relationship with the protagonist Dani Rojas develops, but it doesn't seem it will be the same.
Unlike Vaas, Anton doesn't really sell unpredictability; instead, he sells the mad genius behind it all. Vaas acted out and players never knew what he would do, but Anton seems like he may miles ahead of Dani in terms of plot development. And that's not to mention their relationship with their fellow man—Vaas turned his back on the Rakyat and sister, Anton does what he does for his country and for his son.
He wants Yara to be better, he wants his people to rise above economic sanctions, and he wants his son to be prepared for when he must fill his father's shoes. Methodology is for sure questionable, as Anton believes he can rule with an iron fist and knows what's best for his country, but Vaas' train of thought may have never gone that far.
And this sets them apart in a big way: Vaas was devoid of morals. Vaas wasn't evil in pure black-and-white terminology, but he was nowhere near good either. On the other hand, Anton has morals however misguided they are. He wants better for his people, he wants them to rise above their limits, but he wants his hand on the steering wheel at all times. His morals are perhaps covered up by his role as a dictator, but he's not Vaas nor should he be. Anton seems set on his own legacy, both in-game and in-franchise, and that could go a long way for those who haven't touched a Far Cry game in years.
Far Cry 6 is set to release February 18, 2021, for PC, PS4, PS5, Stadia, Xbox One, and Xbox Series X.