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[Harry Potter] ELI5: How does sacrificial protection(i.e. Harry gaining"blood protection" from Lily's sacrifice) work and is it consistent throughout the series?

Okay I've seen people try to explain this but it almost always seems convoluted and makes me think that it's not consistent and people are trying to make excuses for it.

How exactly does this protect Harry? How does this enable him to burn Quirrell? Does he use these powers any other time?

Can someone please give me a simple explanation and tell me if it is consistent? Thanks.
gpt
# How to Grant Love's Protection

1. Be a Wizard.

2. Someone (henceforth called killer) is threatening to kill one or more people you love (henceforth called lovees).

3. The killer gives you the choice to save yourself. Having the choice matters! If you were just going to die anyway, it doesn't count!

4. Choose to die, then get killed by the killer.

# What Exactly Does it Do

1. The killer—and only the killer—can no longer physically touch the lovees without being destroyed.

2. Spells cast by the killer on the lovees don't work properly. Magical enchantments put on the lovees will be spontaneously dismissed and other spells might bounce off or work at reduced potency.

# Bonus: The Lovees Are Your Blood Relative

1. A third party may cast a special protective charm on the lovees if they are a blood relative of the person who sacrificed him- or herself.

2. This amplifies the original love's protection because blood ties are really important in magic. Even a Killing Curse cast by the killer against the lovees will be fully deflected, with almost little harm to the lovees.

3. To maintain this extra protection, the lovees must live with a shared blood relative. It's ok if most of the time they are somewhere else, but they must spend some time there (e.g., summer break) at least once every year.

4. The killer or any of his or her associates cannot enter the shared blood relative's house.

5. This extra protection is immediately cancelled if either (a) the lovees no longer call the house of the shared blood relative their home OR (b) they reach the age of magical maturity, 17.

6. This special blood protection charm was created by Albus Dumbledore.

# For Dark Wizards: Love's Protection and You

1. There's no counterspell you can use to dispel the protection (whether the base one or the fortified blood relative one).

2. If you happen to lose your body and then recreate it using the blood of one of the lovees, you may affect that lovee as though he or she didn't have the protection.

3. However, even if you use a lovee's blood for resurrection, if that lovee's has the special blood protection, you won't be able to enter the shared blood relative's house.

3. If you use a lovee's blood for resurrection, you might act as a "positive energy Horcrux" for that person, meaning the lovee will not die as long as you live.\*

4. If you use a lovee's blood for resurrection and you have created any number of Horcruxes, your soul can be healed completely if you feel remorse.

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*^(Further conditions might apply. Please check your destiny is intertwined with the lovee's by word of prophecy and that you're using a legendary wand whose master is the lovee.)