(I added "Eversight Ring from act 2, and Helldusk helmet from act 3" to the effects that grant sight in magical darkness section. I don't know if it's a bug, but I tested this and with the eversight ring on, I was able to cast spells and shoot into the darkness. But upon removing the ring, it made my character run into the darkness to cast/fire. It also allowed me to fire out of it. I haven't got the helmet yet, but it has the same wording, so I'd assume it works the same.)
Darkness is a level 2 evocation spell. This spell allows spellcasters to conjure a cloud of darkness in an area within range that obscures and Blinds those within it.
Description
Create a cloud of magical darkness that Heavily Obscures and Blinds creatures within. Creatures cannot make ranged attacks into or out of it.
Circle of the Lands who choose the Swamp Land at level 3 learn this spell automatically.
Way of Shadows gain the ability to cast this spell at level 3, at the cost of 2Ki Points.
Effects that grant sight in magical darkness, such as the Warlock Eldritch Invocation Devil's Sight, Eversight Ring from act 2, and Helldusk Helmet from act 3, allow ranged attacks into and out of this spell's area.
Darkness
Range: 18 m / 60 ft
Creates Area: Darkness
Duration: 10 turns 
Type: Cloud
Disadvantage.
Advantage.
, 
s, and 
s can only cast the spell once per Long Rest.
s who choose the Swamp Land at level 3 learn this spell automatically.
s gain the ability to cast this spell at level 3, at the cost of 2
Ki Points.
Darkness on the Forgotten Realms Wiki