Spike & DrusillaDrusilla was turned into a vampire in London in 1860 by Angelus. She was a pious young woman plagued with visions of the future. Angelus became obsessed with her as she seeked solace in religion, torturing her, murdering her loved one and killing her as she prepared to take her vows as nun, driving her insane in the process.
Twenty years, still in London, she encounted a young poet named William in the streets. Distressed by being rejected by the woman he loved, William seeks refuge in a dark alley. Drusilla follows him, wanting a playmate of her own, sires him.
William assumes the moniker 'Spike' apparently due to his fondness for killing people with railroad spikes (he is also known as William the Bloody... Bad Poet), and join Drusilla, Angel and Darla, wreaking havoc as they go. In 1900, Spike kills a Slayer, and the pair part ways with Darla and the now ensouled Angel. They continue to travel together. At some point, they were attacked by an angry mob in Prague and Drusilla was severely weakened. Later Spike bring her to Sunnydale, hoping to restore her strength.
Despite Buffy's interferences, Spike is able to complete a ritual - with Angel's unwilling help - and Drusilla's power is restored. However, during a fight with Buffy, Spike is crippled and bound to a wheel-chair. The roles are reversed, with Drusilla now caring for him.
Angelus soon returns and Spike, plagued by jealousy, prentends that he is still incapacited and plots against his rival, eventually striking up an alliance with Buffy and flees Sunnydale with an unconcious Drusilla. When she comes around she is furious that Spike betrayed Angelus, and cheats on him with a variety of demons. They eventually fight and break up when she accuses him of loving the Slayer.
Drusilla later returns to Sunnydale in an attempt to bring Spike back to the 'family', but seeing that his loyalty had shifted, she realised he was lost to her and left town again.