The 16-year-old impressed Rovers during a two-week trial with the Championship club last season.
He will continue the remaining year of his academy scholarship at Ewood Park before signing a two-year professional contract with Blackburn.
Burton’s academy manager Mike Whitlow told Albion’s official website: “Our job is to create professional footballers and we want every youngster who comes into this building to progress, develop and get an opportunity and it is a fantastic move for Devarn.
“He’s a great lad with a brilliant attitude and it’s rewarding for everyone involved.
“Last year we had Regan Upton join Wolves and now Devarn has got his chance at Blackburn and of course we have the likes of Matty Palmer, who made his debut for Burton last season.
“We wish Devarn well and all want him to succeed and hopefully we’ve played our part in somebody becoming a professional footballer.”
Rangers defender David Bates hopes to show Alex McLeish he is ready for Scotland honours by shutting out Celtic on Sunday.