The third enemy is the Officer.
Officer is fast and agile. He runs fast and shoots. He wears a black vest, but is still easy to kill. He is the officer elite of the Triad.
It is described in the original RotT specification as follows:
"Officers - Red uniforms"
But I chose this description of Smart Officer:
"Smart officers - Redden their faces, red uniforms with dark flak vests. One and a half times as fast, more hit points, will seek out healing (even secret healing)"
I think it will be the best. Especially since the officer with the black vest was one of the enemies in the prototype from September 1993.
It's also in the original spec art on the 3D Realms website.
credit: Apogee
FB Rise of the Triad: Wolfenstein 3D Part II - FB Site