Hp: Is It Reasonable for the Protagonist to Be Immune to Eating Giant Melons?

[Single female protagonist] [No system] [Growth flow] [High sugar and no knife] Eric traveled through the HP world and unexpectedly discovered that his body could resist the attack of the Death Curse. He used this skill to punch Voldemort, kick Death Eaters, and dominate Hogwarts. Just when he was immersed in the ocean of magic and felt that magic was nothing more than this, he did not expect that there were hidden deeper secrets in the world...