No Fae is an Island - Angel Martinez - Bog

Diego's world refused to stand still in his absence. Now he's no longer sure of his place in it.
Three years ago, Danu banished Diego from the human world for a time. Three years and three days doesn't seem that long to be away from home but time among the wild fae can change a man and the human world returns the favor by changing while he's gone. There's a vampire on Tearmann Island's security force. A curious selkie's followed him home. So much to do to keep the world safe…but Diego's no longer sure he has the right to interfere.
Theo Aguilar started his vampire life on the wrong side of the law. He's killed and knows he's dangerous if he doesn't stay in control every moment. But the fae took him in and Prince Lugh has given him a position of trust. So when Diego and Finn are arrested on a diplomatic mission far from home, he knows his duty. He's striking out on his own to rescue them, a lone vigilante once again, this time for the good guys. The only glitch? The selkie, Limpet, can't seem to understand the alone part.