Neville Longbottom, Was Harry's Friend in the same year as Harry.

Neville's Parents, Alice and Frank, Were Tortured by Bellatrix Lestrange.

Therefore, He was taken Up by his Aunt.

Neville Took Part in The Battle of the Department of Mysteries

Sirius Came and Saved them All, by fighting off Death Eaters,

Bellatrix Lestrange then Murdered Sirius Black.