Offret gjorde det bara så att den mörka Herren inte kunde röra Harry.

Lily's offer gjorde det bara så att den mörka Herren inte kunde röra Harry särskilt. Det fungerade inte på varje person som innebar att Harry skada, eller den mörka Lordens anhängare, bara den mörka lorden själv. I kyrkogården säger den mörka herren att han inte kunde röra Harry efter att Lily har offrat honom.

“You all know that on the night I lost my powers and my body, I tried to kill him. His mother died in the attempt to save him – and unwittingly provided him with a protection I admit I had not foreseen … I could not touch the boy.”
- Harry Potter and the Goblet of Fire, Chapter 33 (The Death Eaters)

Halssvans berör dock Harry utan att ha någon smärta från kontakten med honom, trots att han är en Death Eater i Dark Darks tjänst.

“Harry could hear shallow, fast breathing from the depths of the hood; he struggled, and the man hit him – hit him with a hand that had a finger missing. And Harry realised who was under the hood. It was Wormtail.”
- Harry Potter and the Goblet of Fire, Chapter 32 (Flesh, Blood and Bone)

Detta händer innan Mörkherren använder Harry's blod i drycken för att bygga sin nya kropp, så att han kan röra Harry, så den mörka Herren skulle då inte kunna röra Harry, men Wormtail, som arbetade för honom och agerade på hans vägnar lika mycket som Quirrell gjorde, kunde. Den enda anledningen till att Quirrell inte kunde röra Harry var att huvuddelen av den mörka Herrens själ var i honom vid den tiden.

“But why couldn’t Quirrell touch me?’

‘Your mother died to save you. If there is one thing Voldemort cannot understand, it is love. He didn’t realise that love as powerful as your mother’s for you leaves its own mark. Not a scar, no visible sign … to have been loved so deeply, even though the person who loved us is gone, will give us some protection for ever. It is in your very skin. Quirrell, full of hatred, greed and ambition, sharing his soul with Voldemort, could not touch you for this reason. It was agony to touch a person marked by something so good.”
- Harry Potter and the Philosopher's Stone, Chapter 17 (The Man with Two Faces)

Det fungerar också bara på den mörka Herrens huvudsakliga själ - det fungerar inte på Horcruxes. Harry berörde och interagerade med dagboken, även innan den mörka Lorden gjorde sig immun mot sin beröring.

“Oozing back out of the page, in his very own ink, came words Harry had never written.

‘Hello, Harry Potter. My name is Tom Riddle. How did you come by my diary?”
- Harry Potter and the Chamber of Secrets, Chapter 13 (The Very Secret Diary)

Det var bara den mörka Herrens främsta själ som inte kunde röra Harry, och när han innehöll Quirrell, gjorde det också Quirrell sårbart för Harrys beröring eftersom den mörka Herren delade sin kropp.

Detta förklaras av Dumbledore när han besöker Harry i Hospital Wing efter konfrontationen med Quirrel:

“But why couldn’t Quirrell touch me?”

“Your mother died to save you. If there is one thing Voldemort cannot understand, it is love. He didn’t realize that love as powerful as your mother’s for you leaves its own mark. Not a scar, no visible sign ... to have been loved so deeply, even though the person who loved us is gone, will give us some protection forever. It is in your very skin. Quirrell, full of hatred, greed, and ambition, sharing his soul with Voldemort, could not touch you for this reason. It was agony to touch a person marked by something so good.”

Från orden som jag vetat, verkar det som att den brinnande effekten var unik för Quirrel / Voldemort eftersom de var så fulla av hat. Det låter som om det var specifikt konflikten mellan hat och kärlek som orsakade den brinnande effekten.