XEL, you know more about the world's history and chronology than I do, so explain what science fiction has to do with it?

Science fiction has always been a part of the Heroes universe. Before the Silence (see the chronology), there was science fiction.

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I also have nothing against Ashan, quite the opposite, but I just didn't understand: there was mention of some Sandro - is it a coincidence? Does anyone know?

It's just that Ubisoft wanted to show off and claim that "here's at least some connection to the past." The same goes for Crag Hack and Solmyr.

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There's no point in criticizing LotA; it's better to enjoy it. Ubisoft is unlikely to revive the old universe because it required thinking to create the plot, and in Ashan, there's no need for that.