Derek is generally depicted as a hardworking person, always taking any task given to him no matter how trivial or mundane it might be. As a result, he seems to be emotionally invested in getting things done constantly, which makes his mother worry about his well-being. According to his analyst, Derek also takes it hard when his effort doesn't get due recognition.
Depending on the kind of notes collected, his personality can be expanded upon or turned the opposite way.
- For the Light notes, he retains his industrious self and though he doesn't beat the protagonist in sales numbers, Derek will get good evaluations from customers and superiors alike, only taking time off work to meet his aunt, who was in town in one instance.
- For the Blood notes, Derek becomes a slacker attending wild parties to meet girls and has a tendency of getting drunk and hung over, causing him to skip work. Moreover, he will also be drinking on the job and get a very poor employee evaluation.
The broadcasts shown in the Otherworld Fire area reveals that he was suspected of stealing money from the register, as well as getting an offer to work in another town.
After the protagonist rewrites their past by defeating the Fire Guardian, they receive the promotion instead.
- For Blood, Derek will throw a fit then quit the job.
- For Light, Derek gets transferred to another store.