Sloan Taylor is a Demonic girl she can kiss things to death, and kiss those dead things back to life. Her kisses can be used as ammo too, and can be physically grabbed and thrown. Apparently, she can turn into a werewolf or a vampire on top of these powers, unless the Alpha powers she was going to extract from Tommy and take for herself are not related to lycanthropy and Corey Feldman was only planning on sucking her blood.
She is a bounty hunter, and she was hired by Gil to track Tommy down and lure him to the new Syndicate headquarters. She used Merton's dead body as leverage against Tommy after kissing Merton to death.
On the surface, she seems to be a charming girl who likes Tommy and Merton's sense of humor. But she's good at manipulating their feelings to get them to react the way she wants them to. She told Merton Tommy got grabby with her in the hallway, and she told Tommy that Merton told her Tommy didn't really like girls.
She seemed to genuinely like Corey Feldman, though, until he tied her to a chair and threatened her in order to get Tommy and Merton to save her. The fact the two had saved her did not deter her from carrying out her mission. Merton put his neck on the line against Corey's fangs, and she still killed him with a kiss and celebrated the accomplishment with ruining the page with the picture of him in the Pleasantville High yearbook with another kiss.
She was just supposed to lure Tommy to the new headquarters for Gil and use the kissing power as leverage to get him to go through with the Alpha extraction, but she wanted the Alpha powers for herself.
She was defeated when Tommy grabbed one of her kisses and threw it back right onto her lips.