Nox by Adrienne Wilder

A nude man invades Luca Suarez’s home and protects him from creatures who cannot exist.
Creatures hunting him.
The stranger can’t tell Luca why. He can’t even tell Luca his name.
He remembers nothing until the moment he sees Luca.
The only hint Luca has to the stranger’s identity is a tattoo on his wrist: N o X
Nox doesn’t know who he is, but he’s sure of three things, his memory loss is temporary, the monsters chasing Luca are called Anubis, and his Alpha, Koda, sent Nox to protect him.
There’s just one problem… Koda is Luca’s brother who was murdered five years ago.
With each passing hour, Nox fills in the pieces painting an impossible truth. And with each passing hour, both men find themselves unexplainably attracted to each other.
Something Luca is willing to embrace because he has nothing left to lose.
And one Nox can’t let happen because it could get Luca killed.