Well Julia Sliverstein is her name. Her age is never released officially, but she is most likely around late 30s to early 40s. She's first introduced as the doctor that gives Saya her blood transfusions. She is in fact a medical doctor working for the Red Shield Medical Section. (Mister David is also a member of Red Shield) With the small info released about her past, it is also said that she graduated from Sorbonne University, which is the same university as Van Argeno. It's also seen that she was a smoker at the beginning of the series, but isn't seen during the later part.

Julia is a women that seems to have got it all: the brains, the beauty and doing what she loves, science. But like any women, she also has her heart. Early in the series, it's easy to see she has eyes for David. Problem is, David is too preoccupied with completing the mission of using Saya to defeat the Chiropteran. She is seen going out of her way to even wear a very revealing dress in Vietnam to try to get David's attention on at least her body; but fails.

When Red Shield is broken after the attack by Diva, Julia is given the choice to leave with Collins who has betrayed Red Shield for is own selfish research needs. This offer, to learn more about the chiroptera, is more than Julia can pass up and she leaves with Collins. During the year when the rest of the cast is in England, Julia becomes Diva's personal physician by Amshel’s request. Julia's past with Collins is never gone into detail, but he was probably her teacher or mentor while still in school.

Collins soon becomes very jealous of Julia because of the position she has taken as Diva's doctor, and makes a plan to take her out. This isn't before David infiltrates the Goldsmiths & Cinq Fleches joint-venture laboratory, where Julia is currently working, disguised as a doctor named John E. Hamilton. He is able to gain some information from her, while also trying to steal her pen. David comes back again, wearing a different disguise, but this time Collins is about to have is way. Just as Collins pulls the trigger to kill Julia, David jumps in front of her to take it instead. Collins, even more angry than before disappears and is never seen from again for the rest of the series. At this moment, it seems clear that David really does care for Julia, enough to give his life for her.

Julia agrees to return to Red Sheild after this, but David has been bed ridden while recovering from the gun shot. While still in bed, Julia over looks his sleeping body and kisses him. She can only hope her feelings will reach him and allow him to recover quickly.

After, as the series moves to New York City, Julia has finally been able to get David's heart for her own. They are seen holding hands and smiling at each other during an episode, proof of a relationship between them. In the final episode of Blood+, as Julia is giving Saya another blood transfusion, she is seen wearing a wedding ring and is now pregnant with David's child, letting Saya touch her stomach and making a promise that her child would grow to be friends with Diva’s. Julia gets her happy ending after all, and David wears Hawaiian shirts.