Reign of the Fallen by Sarah Glenn Marsh

Odessa is one of Karthia’s master necromancers, catering to the kingdom’s ruling Dead. Whenever a noble dies, it’s Odessa’s job to raise them by retrieving their souls from a dreamy and dangerous shadow world called the Deadlands. But there is a cost to being raised–the Dead must remain shrouded, or risk transforming into zombie-like monsters known as Shades. If even a hint of flesh is exposed, the grotesque transformation will begin.

A dramatic uptick in Shade attacks raises suspicions and fears among Odessa’s necromancer community. Soon a crushing loss of one of their own reveals a disturbing conspiracy: someone is intentionally creating Shades by tearing shrouds from the Dead–and training them to attack. Odessa is faced with a terrifying question: What if her necromancer’s magic is the weapon that brings Karthia to its knees?