Spike has two parts. The first Spike we meet is the Slayer of Slayers. In vamp face, the cool guy, telling the other vampires about the slayers he killed (“Who am I kidding? I love to brag!”). Then Dru shows up, and he drops his vamp face, we see the other side: Love’s Bitch. Doting on his sick girlfriend and giving her his coat. No one else in the room matters when she shows up.
And that’s Spike. Spike’s greatest moments are when he flips from one to the other. The end of “Fool For Love”, when he goes back and forth and back and forth from one to the other. First he’s the Slayer of Slayers, cocky, taunting Buffy, threatening her and hitting on her as if there was no difference between the two, then he switches to Love’s Bitch, crying after she rejects him. Then he pulls himself together and looks after Buffy with a homicidal glare and is the Slayer of Slayers again. And then he shows up at her house, and she’s crying. And in an instant, he’s Love’s Bitch again.
You often hear the monster-versus-man dichotomy used to explain Spike, with the Love’s Bitch side being the man, and the Slayer of Slayers side being the monster. This matches the visuals in “School Hard”, where Spike is in vamp face as the Slayer of Slayers, and goes into human face when he becomes Love’s Bitch. But it doesn’t entirely fit. I heard someone once say that Spike goes back to his William roots when he sees Buffy crying on her porch, but the thing is, he never really left William. What about Drusilla? For years, Spike was Love’s Bitch for Dru. Doting on her, caring for her. And he was as much a monster then as he ever was. The thing is, Spike is the Slayer of Slayers *because* he is Love’s Bitch.
“Darling, it's who you'll always be,” his mother tells him in disgust, after he turns her into a vampire, “A limp... sentimental fool.”
“Oh, Spike, look at the wonderful mess you've made,” Drusilla says in delight, in China years later, “That's a Slayer you've done in. Naughty... wicked... Spike.”
“Kill her, Spike,” she pleads, years later, about another slayer, who will one day replace her in Spike’s heart. “Kill her for me?”
And even Buffy: “What I want is the Spike that's dangerous. The Spike that tried to kill me when we met.”
Spike will be what the women in his life want him to be, and what the women in his life seem to want is the Slayer of Slayers.
This is obvious even in S2. In “School Hard”, Spike considers tending to Drusilla more important than impressing the other vampires. He makes Dru jealous by obsessing over tapes of Buffy in “Halloween”, but in “Lie To Me”, he lets Buffy and his other victims go in order to save Dru’s life. The most telling moment, of course, is “Becoming, Part 2”. Spike teams up with a slayer against his own vampire kind in order to get Drusilla back. Spike would rather have a girlfriend who is faithful to him than the glory of killing another slayer.
There’s been some debate, in fandom, as to whether the attempted rape came from the monster or man side of Spike. And if it came from the man, would getting a soul actually help? When it comes to Slayer of Slayers and Love’s Bitch, “Seeing Red” is a perversion of both roles. The Slayer of Slayers does not try to rape a slayer on her bathroom floor because she would not admit that she loves him. Love’s Bitch does not make the woman he loves cry and plead. This is why it’s so upsetting for Spike. It doesn’t fit either identity.
In “Tabula Rasa”, the episode before Buffy and Spike have sex for the first time, the Scoobies lose their memories. Fortunately, they have driver’s licenses or other ways of identifying themselves on them. Every character calls themselves by their own name (if sometimes mispronounced) except for two: Buffy choose her own name: Joan. Teenage female hero…and martyr. Possibly crazy. Spike, tellingly, chooses his name from the jacket he was wearing: Randy. A jacket, like the black leather coat he took from Nikki Wood’s body, the same coat he left on the stair railing of the Summers house in “Seeing Red” the last time he was there soulless. His identity always comes from women, those he loves, and those he kills.