Your question makes no sense. Gellert Grindelwald was killed by Tom Riddle in 1998, in the Numengard prison.
Not sure who killed her, it was an accident during the battle between the three men: Albus, Aberforth and Gellert. No, she is a witch.
Voldemort killed him because he refused to reveal information about the Elder Wand.
He is set to appear as Gellert Grindelwald in Harry Potter and the Deathly Hallows.
Gellert Grindlewald
Jamie Campbell Bower will play the young Gellert Grindelwald. It is unknown who will play him when he is older.
Himself: his own Avada Kevadra killed him.
Harry Potter and Twilight are two different fictonical stories therefore a Harry Potter character is not engaged to a Twilight character. However, Bonnie Wright who plays Ginny Weasley in Harry Potter is engaged to Jamie Campbell Bower who plays Gellert Grindelwald in Harry Potter and Caius in Twilight.
Gregorovitch Gellert Grindelwald Albus Dumbledore Draco Malfoy Harry Potter
Harry didn't killed nobody.
No, only the Horcrux inside him was.
No Harry Potter book starts with that.
no