|Scout Sergeant Phalanx|
It's tough to see from this angle, but his left arm is the cybernetic arm from the Cadian Command Squad.
His left arm is bionic, and he has a shank instead of a left hand. He is Roberto, the stabbing robot!
These conversions are not terribly ambitious, but they are very flavorful, and fit well with the Steel Revenants' Mechanicus theme.