At least that's what he started life as in the Citadel catalogue, way back in 1987. He seems to have undergone a few make-overs since then, most notably the addition of a spiffing set of horns.
I got the miniature as part of a job lot of old 1980 minis in an ebay auction. He was badly painted, but a few nights soaking in neat dettol followed by a plenty of good scrubbings with a toothbrush and detergent soon sorted that out.
I painted him up using a combo of foundry and citadel paints, foundry bright red shade 15A as a base for the armour, followed by a few washes of citadel druchi violet. Then I worked up the highlights with foundry bright red 15B and C finally edging out the armour with yellow.