Diana isn’t a Vampire. She is from the Asgardian Realm, specifically Themyscira. She was raised by her mother, Hippolyta and her aunt General Antiope. Diana became one of the fieriest fighters and trained diplomat.
Though she always felt as if she was missing something or meant for more.
Then suddenly through the biofrost, a bi-plane crashed into the ocean. Without hesitation she dived into the waters and saved the pilot. She learned about Earth, and the war to end all worlds.
She knew she had to go back with Steve Trevor to help. She felt as if this was her calling.
Diana went back with Steve, and followed him to the front to try and stop Ludendorff from destroying the Armistice. Instead she ended up facing off with Sir Patrick Morgan, who was playing both sides to the middle.
To discover, he was one of Loki’s.
In the mist of fighting him, she watched in horror as Steve Trevor’s plane was destroyed – she then understood his comment ‘I’ll save the Day – You save the world’.
She then finally understood human love and loss.
After destroying Morgan, she returned back to London with Steve’s friends, determined to stay with the humans, fight for them. For love.
A month later she ended up confronting Jacob Frye and John Rhys, who had a message for her. She traveled with them to Egypt, where she discovered Steve was still alive.
They explained about Vampires and Clans, and that Steve had been Turned. He explained she was his Mate, but do to her physiology couldn’t be Turned. But also because of her physiology she was merely immortal on Earth.
They both ended up staying with the Medjai, working with Henenu aka Henry Jekyll.
Her fondest memory is taking Steven back to Themyscira, where he was trained to fight with her. Even Antiope had given him some admiration even if it was grudgingly.
Today they live between Paris, where Diana works at the Lourve, and Cairo. Steve plays her assistant, hiding his spying easily.