Dunmharu. The Seven Gates.

Seven dimensional gates allow travel to other worlds. Problem is they also allow creatures from other worlds to travel here. Cahal Kearney, a human-Fae hybrid, uses the powers inherited from his Fae father to protect his mother's world from supernatural threats. He is the Dúnmharú; the Assassin. Cahal uses whatever he needs to even the fight - ancient magic from Gaelic mythology and modern magic we call technology. Blood Dragons broke through a warded gate and are mercilessly murdering Legacy witches. Witches like his grandmother. But they aren't the worse threat. They are a tool of the one who brought them to Earth. The one who has decided it is time for humans to relinquish control of the planet. An enemy in the shadows wants nothing less than to rule the planet. If unleashing the terror of Blood Dragons paves the way, then let there be blood and fire. If the only way to discover the identity of the creatures' master is by facing these beasts, the Dúnmharú is prepared for the fight. The future of the planet goes to the winner."The Seven Gates melds Celtic mythology with modern technology to create a hero you will cheer for. Foxe pits a new superhero against incredible odds and pulls the reader into the conflict. The Seven Gates is a mystery wrapped in a thriller."SFFUniverseUK"Finally! A superhero for adults. A thriller that stimulates the libido as it captivates your desire to see the good guy come out on top."Desiree Pachinco, Fantasy Blogger