The Fast and the Furies by Luna Joya

Nolan Bankston isn’t just a cocky gunslinger with a badge and secrets tangled up in my family’s worst tragedy. He’s a wolf shifter and my fated mate. No way this will end well.
Three years ago, a rogue wolf shifter slaughtered me and my family. I swore a blood oath to serve an immortal Fury straight out of mythology in exchange for a second chance at life and brutal vengeance against anyone involved in my family’s murder.
Nolan, a wolf shifter who thinks he’s the gods’ gifts to women, needs my help. Only he’s more than a marshal—he was the best friend of the dead wolf who murdered my family. Except he has proof the real killer is still alive and here in Syn City.
I’m a mortal Fury, a divine dealer of execution for crimes that must be avenged. Even if the signs point to the killer being my fated mate.