To casual viewers of the Marvel Cinematic Universe, Ronan the Accuser is little more than "that angry blue alien with the powerful mallet." But Marvel Comics fans know there's a lot more to the infamous enforcer of Kree law. Ronan has a rich comics history that stretches back to the late '60s, and he is named among the best Avengers villains. He's one of the most significant members of the Kree, a humanoid, blue-skinned race that originates from the planet Hala. With their fondness for conflict and technological innovation, the Kree are basically Marvel's Space Romans.
Ronan is also a member of the Kree Public Accuser Corps, a heavily militarized police force. As the Supreme Accuser, Ronan is effectively the Attorney General of the entire Empire, answering only to the Imperial Minister and the Supreme Intelligence - the bodiless, all-knowing being that governs the Kree. As referenced in Captain Marvel, Ronan is a long-time antagonist of Captain Mar-Vell - Carol Danvers' male precursor in the comics. But his undying devotion to his people has also put him in the crosshairs of the Fantastic Four, the Guardians of the Galaxy, the Inhumans' Black Bolt, and even the Supreme Intelligence itself, making him one of the most notable Marvel villains ever written into being.