In the two years since Danny Brown's breakthrough mixtape, XXX, the Detroit MC has become a ubiquitous figure, a go-to for artists of any stripe-- from A$AP Rocky to Purity Ring to A-Trak-- looking to goose their tracks with an instant spike of adrenaline. And while the self-effacing Brown admits to overextending himself-- "I'm sometimes guilty of rushing through certain feature spots," he tells me-- he's not slowing down.