This mech is no mere steam punk robot. It's a dukes style mech that stands about 15 feet tall and runs on a mysterious rock that if you touched with your bare hands would turn them to ash. However, the rocks found around it were rich with a strong metal that could be manipulated like steel. So instead the power is harnessed and gives way to a new technologies of war. However the man who discovered the rock and designed the first mech was not part of any government or country. So they were created for worthy pirate captains and lords. The governments soon caught wind of this and found the blue prints for the mechs and began building their own. This laid the foundation for a new kind of warfare for the powerful stone.

...ehem... ANY WAY

I got bored one day and started thinking ideas for some pirateish medieval universe where this rock like power source created some cool shit. And maybe there are different variations of rock that give off differnt power to create some elite mechs.

Sorry, I ramble.