There are many ways to get Darkness in MD. Ranging from Equipment (such as armor or jewelry), stores (that enhance items to absorb light), or even spells.

Armour:
-Crown of Darkness
A wicked Noble-Lady wears this as she attempts to bury the city of Candera with the dead!

-Dark Tunic

-Shadow Cloak
Found on a masked thief in Candera

Jewelry:
Pitted Iron Ring (See Jewelry)

Spells:
The Lightsbane spell of Necromancers

also, Riipar in Indel will enchant your items so that they’ll absorb light.