"Well, the groundskeepin’ part’s obvious "nough. As fer the keys—there’s three Keys o’ Hogwarts. The Gate Key unlocks the Gates o’ Hogwarts; with the Gates locked, yeh won’ find a place safer. The Ward Key unlocks the ward room; inside the ward room, yeh can control all the spells on the castle. I hold on ter those two meself. The Headmaster’s Key unlocks the Headmaster’s Chambers; if he’s sacked or quits, the key comes to me, an’ I give it ter the next one. I can also take back the Headmaster’s Key if I think ’e’s hurtin’ the kids."