in 1860, Drusilla was a young girl living in London, cursed with 'the sight'. That is, until Angelus spotted her and she became his latest obsession. Angelus set about visiting every torture he could devise on her, including posing as a priest in the confessional and telling her she was evil, and killing all her family. He finally drives her mad and to a nunnery, on the day she takes her Holy Orders he raids the nunnery, killing it's inhabitants and cavorts with Darla in front of Drusilla before turning her into a vampire. Her madness makes her a very special kind of evil when turned into a vampire and she stays with Angel and Darla, though she soon gets lonely for a male companion of her own and finds herself a young man to sire, who becomes Spike. The pair are as much in love as two vampires can be, and as a foursome, Angelus, Darla, Dru and Spike rampage about London. Angelus is the first to leave the group and at some point Spike and Dru leave Darla and set off on their own adventures. These include a visit to Prague, where they get caught in an angry mob which almost kills Dru and leaves her much weakened. Looking for a cure, Spike and Dru, head for the Hellmouth and here they find that the a ritual involving Drusilla's sire will restore her health. Fortunately, Angel is in the neighborhood and the ritual, though interrupted works restoring Dru to her full power.
Her first act as a strengthened vampire, Drusilla throws a party and gets an old powerful demon, The Judge, as a present. With the help of the newly de-souled Angelus, she and Spike unleash The Judge on the world, hoping to rid it of the plague of humans. Their little plan is interrupted by the Slayer and so Dru is mightily pleased when Angelus comes up with another plan to destroy the world, raising the demon Acathla. Spike is not so keen, however, and betrays both Angelus and his beloved Dru and helps the Slayer save the world, then he and Dru hot foot it out of Sunnydale.
Dru, however, is unable to forgive Spike for spoiling her fun and, with her gift of sight, she can see that he is obsessed with Buffy before he can. Drus soon leaves Spike and goes of with a Fungus demon and a Chaos demon, leaving Spike to return to Sunnydale.
When the evil lawfirm, Wolfram & Hart, resurrect Darla as human, they track Drusilla down and bring her to LA in order to turn Darla back into a vampire, which she does. The pair going on a little massacre in LA and start to gather themselves an army, but Angel spoils their plans, kills their recruits and sets a trap for them which results in them being badly burnt.
Licking her wounds, Dru returns to Sunnydale to find Spike, but she finds him chipped and in love with the slayer and, although she gives it her best shot, she cannot persuade him to go back to his evil ways and she leaves Sunnydale again.