Derek was a sixth year Hufflepuff during Dumbledore's Army and the Year of Darkness. He was a sergeant for Hufflepuff in DA. Derek liked poetry and jazz. He was a vegetarian. He had wanted to be an Auror after school.
Stephen and DerekEditHe began dating Stephen Cornfoot. He asked Stephen out in Derek's thrid year (Stephen was in fourth year). He first met Stephen when he saved Stephen from Crabbe trying to bully Charms notes out of him. The two went to the Yule ball together, but they didn't end up dancing. They got into a conversation about hockey and "why it was so awesome" and a "where are you from" discussion with a Durmstrang student (that went until 2 AM). Stephen had helped him study for O.W.L.s (which he got E's and O's in nine of them). He had planned to move to Canada with Stephen and Stephen's parents. His father does not know that Derek is gay and no one told him, even after Derek died, in the Battle of Hogwarts.
Derek became a vegetarian after he worked as a meat packer when he was 14.