DarkSteel is the name those of this age have given it. It is a weapon from a previous age that has long outlived its makers. It is a giant war golem, made of thick dark steel. It looks like a old style knight, with all the flanges, and covered joints. Giant is not a term thrown about casually. It be 100 long strides tall (100 meters), if the height can be reckoned correctly. It is heavier than anything known. It’s foot prints easily compress the earth at least an Elf’s height.
DarkSteel is still patrolling, “looking” for its last opponent. It has done so for several Elven lifespans, and will likely continue into forever.
Every few decades, DarkSteel lumbers back to this part of the world. Never quite on the same path, he strides through fields, villages, keeps, and cities, as well as any terrain. Like a great storm or earthquake, little stands in its wake. People often rebuild in its wake. It is obvious their memories of it fade and they become confident that DarkSteel will not be exactly here ever again.
Other than a massive resistance to magic and alchemical preparations, DarkSteel is simply an armored form, with armor as thick as a man’s arm. No one can enter it to see the golem wonders there.