My second Ork, this one I drew off the top of my head with no assistance from any models or other artworks, as is possible easy to tell.

DeathSkulls are a clan of Orks that specialize in scavanging parts from the battlezone. They tend to have more captured pieces of armor, weapons, and vehicles. They love the color blue and paint themselves up in it as well as paint their armor and such with it (In Ork kulture, blue is their lucky color, so they believe it will help them scavange more items after battle).

Bonus points to anyone who can tell me what Space Marine chapter they think that shoulder armor came from.