I'm the author of the Histories of the Void Garden series of books. The Leechborn are immortal shapeshifters, the children of the lost continent of Allim. They have lived in the shadows of mankind since time immemorial, warring between themselves over the fate of humanity. 

 In Pyre of Dreams (Book one of the HOVG series) we meet David Beach and his daughter Stephanie. When the US president is assassinated along with fifteen other world leaders, David Beach becomes one of the lead suspects in the investigation into this tragedy. His life seemingly falling apart, when help is offered David learns of the existence of the Leechborn and his world is thrown forever into turmoil.

You can preview the first couple of chapters (click on the book cover to view inside) of Pyre of Dreams at https://www.amazon.com/Histories-Void-Garden-Book-Dreams-ebook/dp/B01GBRH1KC/ref=asap_bc?ie=UTF8

and Princess of the Infinite at 
https://www.amazon.com/Histories-Void-Garden-Book-Princess-ebook/dp/B074655QXH/ref=asap_bc?ie=UTF8