Harry Potter and the Necromancer

Regulus Black, younger brother of Sirius Black. Born in 1961 or 1962, when Sirius was in the first or second grade; in 1980, he drank poison and died at the bottom of the lake in order to destroy Voldemort's Horcrux, Slytherin's Locket. Age of death 19 years old.
And now, this young master is back again, my stupid brother! You must be very disappointed!

Main characters: Regulus, Daphne, Hermione, Sarah,