After rumors had been building, both parties revealed on Monday that Microsoft has bought Mojang, part of the team that developed Minecraft, for $2.5 billion.

Minecraft has sold 54 million copies across multiple platforms and continues to be a profitable product, according to a report from BBC. The sale is expected to be finalized before the end of the year.

Many analysts have said that Microsoft is making this investment to attract more users to the company's Windows Phone devices, which up to this point haven't offered Minecraft. Microsoft has neither confirmed nor denied these reports.

Minecraft continues to be one of the top-selling apps in both the Apple Store and Google Play store, which is where Android users get their apps. Last month, research showed that it was the third most popular game on consoles, even though it had been out a while.

Mojang raked in more than $100 million in profit last year. The company was founded in 2009 and has since grown to employ 40 people. Microsoft said that the Mojang staff would join its game studio.

After the deal is done, Mojang's three founders will leave the company but have assured Minecraft fans that "everything will be OK," according to The Wall Street Journal. But many Minecraft enthusiasts have taken to the Internet to voice their displeasure at the deal.

"Makes me sick and sad. It would kill the gaming community," user EvilBatsu wrote on a popular Minecraft forum.

Mojang has tried to assure fans that the deal won't change much about the open-world game they love.

"Please remember that the future of Minecraft and you -- the community -- are extremely important to everyone involved," the company wrote in a statement. "If you take one thing away from this post, let it be that.

"There are only a handful of potential buyers with the resources to grow Minecraft on a scale that it deserves."

Analysts have said that buying Mojang could be a smart investment for Microsoft, giving them a strong customer base for a wildly popular product.

"Not only is it profitable, but it continues to increase in profits years after its release, largely due to the passionate fan base that invests in building out their own Minecraft worlds," said James McQuivey, an analyst with Forrester.