Hogwarts: Is It Reasonable for Me to Cast Spells and Add Mana?

Hogwarts, unlimited mana stacking, decisive killing, and multiple female protagonists! Traveling through the world of Harry Potter, Ethan received the wizard selection system on his eleventh birthday. As long as he makes a choice, he will be encouraged! With the help of the system, his spellcasting can infinitely superimpose mana: in the first grade, he learned to chew a big melon, in the fourth grade, he single-handedly defeated Voldemort, and in the seventh grade, he challenged the God of Death! Sorting Hat: "My dear, I still recommend that you be sorted into Azkaban. Nurmengard is also fine." Malfoy: "No, Ethan didn't hit it, it fell on me." Mag: "Ethan, change the castle back quickly, we have no place to go to class!" Dumbledore: "Merlin's beard! Apparition is not allowed in the school. How on earth did you do it?" Voldemort: "Impossible, absolutely impossible! Why is chewing a big melon useless to this guy?!" When Voldemort led his men to attack Hogwarts, Ethan launched Avada Kedavra like a lightning chain, killing all the Death Eaters in one wave... Ethan: "You may think this is cruel, but we call it efficient." This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.