Fan Fic / 3 Slytherin Marauders

Harry & Dudley flee an abusive Vernon - to Severus Snape. Severus finds a home for himself & the boys with dragons and hunt the Horcruxes from there. The dragons - especially one - become their allies. Tom R is VERY different.
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3 Slytherin Marauders is an AU Harry Potter fanfiction written by severusphoenix, found here.

Petunia Dursley, Dudley Dursley, and Harry Potter leave 4 Privet Drive and — after Petunia recovers from being shot — take shelter on a dragon reserve, thanks to Severus Snape. With help from Lucius and Draco Malfoy, Rosmerta, Tom Riddle, ex-Auror Hugo Savage and a dragon named Yvane, they start hunting Voldemort's Horcruxes.

3 Slytherin Marauders provides examples of: