Ignite

In one day, Derek Hale's life was completely destroyed. After the accident that claimed most of his family, Derek and his sister Laura seek revenge against those responsible: the Argents. But the fight isn't one-sided, and it's not long before Derek and his sister are in completely over their heads.

Fandom: Teen Wolf
Ships: Kate Argent/Derek Hale, Stiles Stilinski/Derek Hale

This story does divert from canon, and makes some changes to the ages of characters for plot purposes.