Fairies Sorcery and the Greek Gods

The book is about how God himself gave an old man named Jack the power to wage a war against a race of fairies and guardians that are taking over the world. Merlin is alive and is teaching him magic from a book they got from Medusa after she was put down. Zeus is sent to take care of Jack and switches sides; he never liked the council of Gods. They rescue Venus, Zeus's true love, from a painting she is imprisoned in. Poseidon comes into the picture, getting his trident back, and comes to find out that his true love was taken from him and was Calypso.