Something was bugging Stiles: an old case gone unsolved since his father was a deputy. Derek's father was murdered by persons unknown and it left a long and deep chasm in Derek that went beyond Paige and his family. Bonds between father and son go beyond words. His father was not a wolf, but (an idea for here and his name being Thomas) born of wolves, unable to change without being turned. This old case had all the hallmarks of hunters born in the lineage of Gerard Argent, excluding Chris and Allison.
Derek told his husband about Thomas. He was human, born of two true borne, yet had half the strength, stamina and speed of a beta. Derek shared a unique empathic bond with his father: something no one else had. When Thomas was dying, Derek suffered the worst nightmare any child could endure and within that dreamscape saw those responsible. Derek had no way of knowing what he felt nor could he convey in words.
This is the complicated part: another artist drew material with Derek as a young werepup. The above story links the two formats together. I originally thought you had drawn the material in question. It is deeply moving, reaching back to then and now, creating a tale spanning two or more artists.