Sony doesn't sound thrilled Microsoft is buying Call of Duty maker Activision

A Brazilian governmental filing has given us a rare glimpse into Sony's thoughts on the impending $69bn Microsoft buyout of Activision Blizzard - and specifically, the fact that Xbox will soon own blockbuster first-person shooter franchise Call of Duty.

In Brazil, companies within the same sphere of any such corporate transaction are asked for their thoughts on deals of this magnitude. And, intriguingly for us, Brazil also posts all of these details online (albeit in some cases with redacted passages).

Sony's response is largely public, and contains a number of arguments which paint the potential of Xbox owning Call of Duty in a problematic light (as spotted by ResetEra, and translated for us by Eurogamer Portugal).

To begin with, Sony argues that Call of Duty is a franchise with no rival - something even EA's Battlefield might privately agree with.

Entries into the Call of Duty franchise "tend to be long-running franchises with big budgets, multi-year development cycles, and fanatical followings," Sony wrote. "And despite large budgets and resources, no other developer has managed to create a franchise to rival Activision's Call of Duty, which stands out as a gaming category in its own right."

Sony describes Call of Duty as "an essential game", "a blockbuster, a AAA-like game that has no rival" and quotes a 2019 study that found COD to be the only video game property that has broken into the top 10 most lucrative entertainment franchises globally, alongside "powerhouses like Star Wars, Game of Thrones, Harry Potter and Lord of the Rings".

More intriguingly, Sony suggests that Call of Duty "is so popular that it 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 rival it".

This is a fascinating argument for Sony to be making, since Sony itself has closely partnered with Call of Duty over the past couple of console generations, offering perks and early access to those playing COD on PlayStation.

"Call of Duty is heavily entrenched, so no rival - no matter how relevant - can achieve it," Sony concluded. "Call of Duty has been the top-selling game for nearly every year over the past decade, and for its genre, it's overwhelmingly the best-selling game. It's synonymous with first-person shooters and essentially defines that category."

For its part, Microsoft has previously committed to launching Call of Duty games on PlayStation "beyond the existing agreement and into the future". This year's Call of Duty Modern Warfare 2 and Warzone 2.0 will both launch on Sony platforms.

Beyond this, it has been reported that the Call of Duty franchise will take an unprecedented break in 2023, before Black Ops studio Treyarch's next title arrives at some point after that. This game is also believed to be part of PlayStation's existing agreement, suggesting nothing little will change - for now.