Eternium
Eternium can refer to:

Eternium (also called Eternium: Mage and Minions, in short M&M) a 2014 Diablo-esque RPG game developed by DreamPrimer (earlier called SnowGlobe Games) and published by MakingFun Inc. for Android, iOS and Microsoft Windows 8,1 and 10 (also available on Amazon) with future development expansions and updates.
Eternium, a fictional planet in the Futurama series first seen in The Day the Earth Stood Stupid.
Eternium, a metal from the role-playing game Ancient Domains of Mystery
Eternium, a metal from the role-playing game World of Warcraft expansion pack The Burning Crusade.
Eternium, a 2004 album by the band Diablo.
Eternium, a metal (the strongest metal) from the planet Eternia in the T.V. Series He-Man and the Masters of the Universe