Debbie Hemlock is a young girl who Darren meets after becoming a vampire, and who quickly becomes his main love interest. It should be noted that Debbie actually has darker skin and is considered to be black in the novels, whereas she has lighter skin in the manga.
[spoiler]Debbie and Darren end up meeting years in the future, her current profession being a high school teacher. It is revealed that they are both still romantically interested in each other, but Debbie rejects his advances, stating that it is inappropriate for them to be in a relationship, considering the fact that he is her student.
It is later explained to Debbie that Darren is in fact a vampire, and she openly chooses to support him during the War of the Scars. She aids Alice Burgess in recruiting the Vampirites, humans who are able to use weapons against the Vampaneze. The two of them are shown to be very close, as Alice is always seen comforting Debbie in times of tragedy within the series.