Leif and Jessica are minor characters from Hellsing.
They are newly turned vampires, comparatively weak and not even being able to fight without bullets.
For over a week they pillaged homes and killed people, afterward scrawling words with the blood of the victims on the walls of their homes. They believe that after nine more killings, they will become invincible and everlasting. However, Hellsing soon hears about their ventures and sends Alucard and Seras to kill them both. Alucard is perturbed that these lowlifes would stoop this low, and easily kills Leif; Seras, realizing her powers as a vampire, is able to shoot Jessica through the heart at long range, without the aid of a telescopic sight.