Sony believes 'Call of Duty' will sway people to buy the Xbox.

In new documents submitted by the PlayStation maker for Brazil's regulator, Sony hailed the first-person shooter series, the world’s best-selling video game franchise, as "essential" and a major factor as to why gamers could choose the rival console, along with Microsoft’s Activision Blizzard acquisition.

The regulator had asked for the opinion of Sony and other gaming giants such as Ubisoft, Warner Bros and Riot Games on the major acquisition.

Sony wrote: “Activision’s Call Of Duty is an essential game: a “blockbuster”, a AAA-like game that has no rival. According to a 2019 study: “The importance of Call Of Duty to entertainment in general is indescribable. The brand was the only video game IP to break into the top 10 of all entertainment brands among fanatics, joining powerhouses like Star Wars, Game Of Thrones, Harry Potter and Lord of the Rings.”

Sony continued: “Call Of Duty influences users’ choice of console and its network of loyal users is so ingrained that even if a competitor had the budget to develop a similar product, it wouldn’t be able to compete."

The video game firm made the point that "players would hardly switch to alternative games" because they wouldn't want to "lose their skills" and friends made playing the game.

Sony added: “Call Of Duty generates strong connections with players. The franchise’s memorable narratives and characters lead to a rich gameplay experience and its long history has created an unparalleled level of familiarity.

“Activision has published Call Of Duty titles every year since 2003.

“Players have become familiar with the game’s setup and mechanics. They’ve honed their skills in the game’s multiplayer over the years, striving to climb to the top of the leaderboards.

“There’s even a sports space just for Call Of Duty. The Call Of Duty League – with prizes for winners running into the millions. To say the least, players would hardly switch to alternative games as they would lose that familiarity, those skills, and even the friends they made while playing the game.”

Earlier this year, Head of Xbox, Phil Spencer, reassured gamers that 'Call of Duty' would remain on PlayStation.

He tweeted: "Had good calls this week with leaders at Sony. I confirmed our intent to honour all existing agreements upon acquisition of Activision Blizzard and our desire to keep Call of Duty on PlayStation. Sony is an important part of our industry, and we value our relationship."