Wearing a full set will grant the player 80% damage reduction, as well as invincibility to lava, drowning and all mob damage. However, fall damage and explosions (e.g. TNT, creepers) will still damage the player slightly. It can be upgraded to Red Matter Armor for even greater damage reduction.
In multiplayer, due to the fact that the Nanosuit can be instantly broken by the Nano Saber, Dark Matter Armor is a better alternative, until either the Quantum Armor is obtained or the suit is upgraded to Red Matter. Since the armor requires no fuel and has very high durability, no energy needs to be directed into keeping the suit active. It should be noted, however, that a player wearing Dark Matter Armor can be killed in one hit with the Diamond Warhammer's special attack.
A full set of Dark Matter Armor is equal to 3,342,336 EMC, equivalent to 408 Diamonds.
RecipesDark Matter Helmet - 696,320 EMC
Dark Matter Chestplate - 1,114,112 EMC
Dark Matter Leggings - 974,848 EMC
Dark Matter Boots - 557,056 EMC