This description's a bit tricky, so let's take it in stages...

Countermay: The Tapestry of Worlds, the crossroads of civilizations beyond imagining. After a thousand years of war, Countermay is dying. Battles, curses, extraterrestrial parasites, demonic influence, and other hazards have ruined much of the planet. The food is running out, and the threat of starvation looms. The only way to save Countermay is to seize undisputed control. Until then, armies march, fed with the ever-dwindling food as they churn farmland into mud with their boots. Can you save Countermay from its invitable doom?

Romance of the Nine Empires is a fictitious interactive collectible card game (CCG) set in the fantasy world of Countermay. In the game, players assume command of one of nine vastly different warring factions — including steampunk aliens, a dark god-king's crusade of conversion, displaced WWII-era American GIs, and a risen empire of the undead — to expand, glorify, or defend their empires. Through its fictitious fifteen-year history, players have shaped the world of Countermay through their individual and collective achievements, and the results are reflected in the story and the current state of the empires. That concept was inspired by the Legend of the Burning Sands CCG, which in turn is based on the Legend of the Five Rings CCG: in those real-life games, tournament results affect the actual story in future expansions.

The plot of the 2013 movie The Gamers: Hands of Fate revolves around the fictitious game. Within the movie itself, AEG was the publisher of the game, but as a result of Kickstarter funding for The Gamers: Hands of Fate, it decided to create a real-life version of R9E. The real-life release is not a collectable game, but a boxed set with a set distribution of cards. This boxed set represents the fictitious 15th Anniversary World Championship Edition of Romance of the Nine Empires, and (to slip into the movie storyline for a second) it holds the decks used by the top-placing characters for each faction that made it to the quarterfinals at the 2012 World Championships at Gen Con Indy.

So there's 3 levels of reality at play here:

the CCG game called Romance of the Nine Empires, pictured in the movie The Gamers: Hands of Fate, which is played by the characters at Gen Con Indy 2012 and is 15 years old;
the fantasy world of Countermay, which is pictured in the CCG game and whose history is shaped by the players of the CCG game;
the real card game Romance of the Nine Empires, edited by AEG in 2013, which comes in a boxed set and is inspired by (and presented as) the fictitious CCG.

Berserk: Heroes