After the killing of Dumbledore, the Runes Professor John Russel helps Harry. During the summer Harry is elected by Higher Magic as White Warlock which brings him more in touch with his Magic. He selects 12 companions for his fight. These are, Russel, Remus, Tonks, Fred, George, Hagrid, Neville, Luna, Ginny, Hermione, Ron and Dobby.
Voldemort allies with The Knight and Companions of Waldpurgis – an eugenics group. Up to the final confrontation several members die: Hagrid, Russel, Fred and Ron.
DrT writes:
The story of Harry’s Sixth and Seventh year in two parts. Part I: HBP as seen through the eyes of Runes Professor John Russell (‚Smoke‚). Part II: Harry, Hermione, and Ron go after the remaining Horcruxes, aided by Luna, Ginny, Neville, Remus, Tonks, and Professor Russell (‚Companions of the White Warlock‘).
The story can be read online at FicWad.
There is also a PDF of the story.