A mysterious vampire who enters into Sunnydale with his mistress, Drusilla. To repeat, Spike is a very mysterious individual who can be very hard to read. He appears to be very loyal to Drusilla, and is a lot more up to date with the modern world, which helps him fit in more. An example includes Spike luring Xander into a trap by texting him from Buffy's lost phone.
The first person we see him get acquainted with is Cordelia. In an odd way, the two seem to hit if off with Cordelia even appearing to have a crush on him. How far this will go & what effect it may have for Drusilla remains to be seen.