Yep, they are indeed metal. They come out like this

and they sing "By moonlight, we ride, ten thousand side by side. With swords drawn, held high, our whips and armors shine. Hail to thee, our infantry, still brave beyond the grave. All sworn, the eternal vow, the time to strike is now. Kill, kill, woooaahhh. Kill, kill, woooaaahhhh. Kill, kill wooooaaahhhh. Kill, kill woooaaahhhhhhhhhhhh" (from Manowar's Battle Hymns)
They also sing Steel's songs, especially Heavy Metal Machine. When they are in a more relaxed mood, they sing that ballad from Steel.