Life debt

A Life Debt is a magical bond formed between one wizard or witch who saved the life of another. The one who owes the debt to the savior would one day repay the deed by doing something beneficial to the said savior. Such a bond can be formed between even the worst enemies, and regardless of whether either of the two want it or not. As this bond is magical binding, the indebted could commit the repayment without acknowledging it, or even against their will.

Known Life Debts

 * James Potter, in his fifth year, saved Severus Snape from a near-fatal prank that Sirius Black played on him, involving luring Snape to the werewolf Remus Lupin. As such, Snape owed James a life debt, despite hating James all times. This was repaid when Snape repeatedly protected James' son, Harry.
 * Harry Potter, in his third year, protected Peter Pettigrew from being murdered by his former best friends, Sirius Black and Remus Lupin, for treason, and instead asked for him to be transferred to Azkaban. Though Pettigrew escaped, he owed Harry a life debt. This was repaid when Pettigrew let out a rare moment of mercy at the Malfoy Manor's battle, and released Harry from a choking hold with his silver hand. Unfortunately, it was this debt that caused the silver hand to kill Pettigrew for showing weakness.

Appearances

 * Harry Potter and the Philosopher's Stone
 * Harry Potter and the Philosopher's Stone (film)
 * Harry Potter and the Prisoner of Azkaban
 * Harry Potter and the Prisoner of Azkaban (film)