The Obsidian Dagger

The Obsidian Dagger is the first book in the Celtic Mythos series. The story is set around Brendan O’Neal, a 17-year-old American, and his younger sister, Lizzie. They are compelled to step in when a crazed witch, armed with a magically forged and terrifyingly potent Obsidian Dagger, threatens to annihilate humanity and seize control of the magic clans in the Celtic Isles.