The Witcher series has sold over 6 million units since its debut, developer CD Projekt RED has revealed. It comes as the critically-acclaimed RPG series turns six.

CDPR’s first Witcher title dropped in 2007, and since then has gone on to be a go-to series for hardcore RPG enthusiasts. The third game, The Witcher 3: Wild Hunt is due on PC, PS4 and Xbox One in 2014.

Speaking with Eurogamer, studio head Adam Badowski said of the milestone, “CD Projekt RED was built on the idea that giving gamers more is always worth it.

“Since the very beginning of our journey we have seen that the approach of inviting gamers into a dialogue with the developer is really important and can shake up the – sometimes self-destructive – business side of games. We hope you’ll stay with us for the years to come and that we will continue to make these changes together.”

You can see a big Witcher birthday infographic rammed full of stats here, along with this lovely piece of sixth birthday artwork.

Meanwhile, the studio’s other project Cyberpunk 2077 has been quiet recently, and the team has stated that it will ‘probably’ come to next-gen. Check out what they said here.

Are you a fan of The Witcher? What’s your take on the sales figure? Let us know below.