WARNING: The following contains spoilers for The Walking Dead #193, by Robert Kirkman and Charlie Allred, on sale now.
The final issue of The Walking Dead reveals the fates of the remaining characters while providing a snapshot of the society that's formed in the years since the death of Rick Grimes, in no small part because of his actions and sacrifices. There's government and law within an expanding Safe Zone, where children grow up never having seen a walker.
However, the finale also adds one more flourish of world-building: the in-universe name for The Walking Dead's zombie apocalypse.
End Of Days
The Walking Dead has never been interested in exploring what caused the end of its fictional world. There were no radioactive satellites or infected monkeys; the dead simply rose, and the living had to fight to survive.
In the midst of that chaos, during which a walker herd might overtake an encampment at any moment, or survivors with less-than-altruistic goals might attack, there was probably little desire to pin a name to the apocalypse. But now years removed from that time, the reemerging civilization is coming to terms with its history. And, just as we might refer to the Jazz Age or the Industrial Age, the people have given the era a name.
Although we still don't know the cause of The Walking Dead's zombie apocalypse, and likely never will, Issue #193 reveals the survivors refer to the dark days in which the dead walked as "The Trials." Judge Michonne Hawthorne, who serves as a kind of one-person Supreme Court, admits while handing down judgment on Carl Grimes that some of her own actions during that period seem demented in retrospect.
It's a nice final touch for the finale, giving the world of The Walking Dead a sense that it has moved on, that those days are well in the past. New generations will learn about The Trials, and the heroes they produced, but they will not have to live through such tribulations. It's the world Rick Grimes wanted so badly. It proves that the members of society, in whatever form, can unite behind a shared history. More than trains, more than courts, more than anything, this proves humanity can move past the zombie apocalypse. That makes it a perfect revelation for the final issue of the series.