The Banshee and the Beast - Lydia Martin

In which Deucalion has a son whom he and his wife abandon after he becomes blind and Talia Hale takes care of until the house fire, which leads to Derek taking care of the boy and raises as if he's his own.

Nathaniel was not only born a wolf but also had two powerful alphas as parents. When he got older he had killed an alpha who attacked him out of self defense leading to him becoming an alpha and a very powerful one at that. At first he couldn't get enough power but only killed those who deserved it and only wolves as well. All the power he collected added up and not only that, he's very intelligent and is very good with strategy.

To get to the point when Derek calls him for help with the kanima and Nathan comes, but not only does he stay for the man that's basically his dad, he stays for a certain strawberry blonde that happened to catch his attention.