"Nearly there!" Harry panted as they reached the corridor beneath the tallest tower. Then a sudden movement ahead of them made them almost drop the crate. Forgetting that they were already invisible, they shrank into the shadows, staring at the dark outlines of two people grappling with each other ten feet away. A lamp flared. Professor McGonagall, in a tartan bathrobe and a hair net, had Malfoy by the ear.
"Detention!" she shouted. "And twenty points from Slytherin! Wandering around in the middle of the night, how dare you ––"
"You don't understand, Professor. Harry Potter's coming –– he's got a dragon!" "What utter rubbish! How dare you tell such lies! Come on –– I shall see Professor Snape about you, Malfoy!"
(Harry Potter and the Sorcerer's Stone)
Shall is used for saying what you intend to do in the future, and will is used for saying that you are willing to do something or that you intend to do it. Then which is the stronger expression, "I shall see Professor Snape about you" or "I will see Professor Snape about you"?