How did a game with an unexplained story turn into a religion over time?

Although it says “PS4 (PlayStation 4)” on the box that I am holding, Shadow of the Colossus is actually a game released for PlayStation 2 in 2005. The one in the photo is the version released for the new generation game consoles in 2018. Nothing was changed except for the graphics. The story, the environment, the dialogues, even the birds and the fish were kept the same.
Let me briefly talk about the plot of the game. Mono, a woman that the protagonist Wander cares about, was sacrificed by the tribe’s shamans, as they believe that she had a “cursed fate.” Getting angry at this, Wander steals a magic sword from his tribe and travels to the Forbidden Lands with Mono’s lifeless body. A shaman had told Wander that, in the Forbidden Lands, there was a being that could revive the dead. Coming to the Forbidden Lands with Mono’s body, the magical sword, and his horse Agro, Wander makes a deal with Dormin, the being that the shaman was talking about. Dormin asks Wander to find and kill 16 colossi living in the Forbidden Lands. If he succeeds, he promises, Mono will come back to life. So, you take control of Wander from then on and try to find and kill those 16 colossi one by one.
This is the plot in its most basic terms. So how did this game turn into a religion over time?
Shadow of the Colossus is a minimalist game built around the concept of “obscurity.” In the game, we have Wander, lifeless Mono, our horse Agro, 16 colossi, and Dormin with whom we made a deal. Although the Forbidden Lands are vast, there is no other person than we encounter. No one! This adds to the theme of obscurity. We don’t know what these lands are, who built those structures, who walked around these lands before us.

Since our characters do not talk to anyone, we can neither learn their past nor their motives. In fact, we can only learn our protagonist’s name, “Wander,” in the Credits screen at the end of the game. Otherwise, his name is not mentioned in any way.
Even the relationship between Mono and Wander is not explained. We do not know if Mono is Wander’s lover, wife, or sister. Even the language the characters speak is an artificial language created just for the game. We learn what the characters say from the subtitles. Some speeches have no subtitles, so we can only guess what is being said.
Although no one lives in the Forbidden Lands, it is full of ruined structures, worn paths, and specific mechanisms. There is evidence that people used to live there in the past. But there is neither an inscription nor a skeleton that tells something about these people. We don’t know what happened to them.
So, when we play the game, we have to create our own story, our own myths. Some think that Mono is Wander’s lover, others think that she is from his family. Some believe that all the people in the Forbidden Land had died a long time ago, and some believe that they had just left. Some believe that the colossi are evil, and some believe that they are actually innocent. No matter how consistent these myths are, there is no way to prove them. The game does not tell us the answers. It hides them. All of these unexplained back stories, unanswered questions led to the creation of myths. Just like how the Greek created myths around Ares, Poseidon, or Hades to give meaning to the unexplained natural events, players created myths in order to explain the world of Shadow of the Colossus. In the end, the game needed an all-mighty god, a Zeus, to unite these myths under one deity to create its own religion.
Shadow of the Colossus’ Zeus appeared in 2007, and its name was “The Last Big Secret.”
Believing that the Forbidden Lands host a secret that no one has noticed before, players started to roam around the lands and seek the last secret. The players believed that a final secret existed and that it would deepen the story, reveal the unknown things, answer the questions that they have been asking. This last step turned Shadow of the Colossus into a religion. The players united under the notion that the “Last Big Secret exists,” and they committed themselves to finding it. They even gave themselves a name; “Secret Seekers.”
In his book Sapiens, Harari claims that all universal religions consist of two elements. The first one is that a religion “adopts a universal superhuman mechanism that is valid anywhere, anytime.” Secondly, people try to “spread this belief to everyone.” This is what transformed Shadow of the Colossus’s “Last Big Secret” into a religious phenomenon. The players believed in the existence of the “Last Big Secret” that could explain everything, that could give more meaning to the game. They shared this belief on forums and websites. Like the emergence of Greek mythology, they first formed their myths and then united them under their own Zeus, the “Last Great Secret.” Whatever path they need to follow to establish a religion, they have, maybe unintentionally, followed that path.
This trend that started in 2007 is still profound in forums and websites. Players are still coming together to discuss their theories and talk about their discoveries. The “Last Big Secret” is yet to be found, but the players have not given up. “Even if you don’t believe that the ‘Last Great Secret’ exists, I do,” they responded to the people, who thought that these people were just chasing a wild goose.
So do I believe the “Last Big Secret” exists? Definitely. These lands are just to big to be left empty. Just like how our world is.
The video below is the intro of the game. Watching it could introduce you to the theme, atmosphere and the story of the game. As the scene is 15 minutes long, I humbly advise you to open up some snacks and watch it in full screen.