Adamantium is an indestructible metal alloy that exists in the universe of Eternal Champions. In 1994, Tokyo was supposedly advanced enough for Nakano Industries to create it and utilise it in its weapons. Something covered in this shell was first seen protecting a mecha piloted by Nakano whilst taking on the nine Champions. Six of them had ventured to The Cyberdome in 2345AD to collect a Bio-Keyedgun capable of helping them rescue their friends, but the firearm was unable to pierce adamantium 5cm thick. However, the metal was much less rigid on the inside, with Trident destroying the machine from the cockpit.