Severus's Last Parting Gift After Death

AU story. After Lily did not forgive Snape for the Mudblood insult, Severus did a ritual that has everlasting consequences, but at the cost of his own life. As a result, history has changed in ways that were never imagined. However, the majority of the things remained the same as in canon. What will happen to everyone at Hogwarts? Character death and major/minor character bashing