"Brought across" in 1880, William the Bloody (known for his "bloody awful" poetry) became the infamous Spike - taking his name from an affinity for driving railroad spikes through people's heads. His sire, Drusilla, took him as a lover and they toured the world with Angelus and Darla.

In 1900, Spike killed his first Slayer. He and Dru left the other two vamps, and continued their rampages. In 1977, Spike killed his second Slayer. He was rebellious and vicious, driven by emotional wounds received while still human. No longer could Spike merely let something go - now when he puts his mind to something, no one can stop him.

When Dru was nearly killed in Prague, Spike took her to Sunnydale, the Mouth of Hell, to find a cure for his stricken lover (physically if not mentally). There, he was constantly thwarted in his efforts by the Slayer - Buffy Summers.

Forced to team up with her temporarily, Spike therefore lost the respect of Drusilla. The vampire's obsession with Buffy grew, until he could think of nothing but killing her.

This plan was hampered when the Initiative named him "Hostile 17", placing a chip in his head that prevented him from doing violence to humans. In this new state, his obsession with Buffy was forced to change. Now, these strong emotions have become a romantic attraction.

Spike's tenacity (or stubbornness) will not allow him to leave Buffy alone. If he can't kill her, his feelings must find another outlet. Hence the crush. Buffy seems to be aware of his feelings, but has none but hatred for him. While he's harmless, however, she can't bring herself to stake him - no matter how much he interferes.

Spike is a vampire like no other - always a rebel, an outsider. And it seems he will always remain that way.