can someone give me brief intro of bellatrix lestrange?????

bellatrix lestrange is Sirius's cousin and Draco's aunt. she is the one who kills Sirius at the ministry and is Naracissa's sister naracissa is Draco's mom. She is the Dark Lord's most faithful servant she was a Black before marriage. she was the one who tortures Longbottoms (Nivelle's parents) to insanity. She also makes the 'Unbreakable vow' with Snape to protect Draco