Klartri or Black Night Trilogy - Michael Ostrogorsky

A coven of shape-shifting witches comprised of a pandemonium of parrots and one black cat, led by a coffee-swilling blue-skinned goddess named Princess Tara, enlist the help of a trio of Seattle history professors to seek magic to stop a god of war and his goddess of death intent on destroying our world to restore theirs. The professors discover they face a conundrum no book or library can address. How do they defeat a goddess who controls death and time? Can they? Our heroes and villains bounce across the galaxy and dive into the depths of time to search for a solution. They discover that reality and time itself is as fluid as a glass of cold beer.