Get Venture Co. Explosives from any of the Venture Company units at Swindlegrin's Dig and use them to obtain a Stormwatcher's Head. Bring the Stomwatcher's Head to Rejek at Frenzyheart Hill.
Rejek hears tales of giant metal men on faraway Stormwright's Shelf. Far to northwest, outside basin's lip, you will find it.
Imagine Rejek using heads of giant metal men as helmet. Make Rejek unstoppable! Make Rejek mighty!
You get for Rejek, but metal head might not come off metal body easy. Maybe steal bombs from little green men and their friends at Swindlegrin's Dig near Suntouched Pillar? Use bombs to get head off metal body, then bring to Rejek.