Madantium lg

Madantium is an extremely strong metal used to upgrade the barracks. It is required from Barracks level 5 onwards.

You get it from Boss Clash battles, Black Market and some events.

From barracks level 20 onwards you'll also need Rock Block, also won from Boss Clash.

It can be Synthesized into Refined Steel at the Forge, which is needed from level 71 onwards.