"Alright."
William appreciated this about Lupin. As long as the requests were reasonable, Lupin generally wouldn't refuse and would even readily agree without beating around the bush. Dealing with someone like this was indeed hassle-free.
"So then..."
Seeing Lupin nod, William turned his attention back to the projection in the Meditation Basin. On the narrow glass platform, Harry was caught in a fierce battle with four goblins. Goblins themselves didn't have particularly strong combat skills, but the ones he was up against were those that had participated in the Goblin Rebellion a century ago.
Back then, the rebellion's leader, Lanlock, had mastered a power akin to Ancient Magic, which significantly strengthened the rebel goblins. This made the four-goblin squads very cohesive, with two warriors in front and a priest and archer behind—a very standard ironclad formation.
At that moment, Harry was trying to figure out how to get past the two warriors aiming to axe his knees, in order to attack the goblin casting Healing Magic at the back.
The goblins' magic system was similar to that of House-Elves, quite different from wizards. They didn't use much Magic Potion for healing; many of their spells were sufficient.
However, Harry's decision was clearly wrong. With little magic power left, he couldn't maintain the Iron Armor Spell. Just two exchanges later, one of the goblins severed his knee, and the piercing pain made him cry out in agony before the next axe blow sent him into total darkness.
"Ah—"
The boy clutched his knee, wailing as he sat upright. It took half a minute for the phantom pain to finally fade away.
"Not bad."
Handing Harry a prepared orange, William comfortingly patted the boy's shoulder. While he wasn't satisfied with Harry's progress speed, he didn't intend to say it directly to his face. You had to give these minors some confidence; constantly demoralizing them wouldn't work if you wanted to teach students.
"They are too short."
Harry grumbled as he stuffed the orange into his mouth, easing the dizziness in his head. He looked up and saw Lupin smiling at him. "Professor Lupin!" he exclaimed, quickly discarding the orange peel and standing up from the recliner.
"No rush, you need some rest now—"
Lupin raised a hand to push the boy back down. As one of the first to experience dream magic combat, he was well aware of the unpleasant feeling of waking from a dream—the real sense of death and suffocation was just too tormenting.
"Times have changed; don't worry, the aftereffects aren't as severe now—"
William waved a hand, signaling Lupin to stay calm, then turned to Harry to explain his arrangement.
"...Practice the Patronus Charm? Of course."
Hearing William's plan, Harry instinctively glanced at Lupin, then quickly nodded eagerly—anything was better than that "force-feeding" education (beating).
"But letting Harry face Dementors directly might be too dangerous? Unless you plan to stay by his side, then disregard what I said."
Suddenly, Lupin interjected. He doubted his Patronus could repel Dementors of the level encountered on the train anytime soon. Weakening them was another story entirely, but since William asked him to teach, he figured William intended to slack off...
"...Maybe that's true."
William was so accustomed to casting Patronus flash bombs that he had subconsciously overlooked this. Neither of them had the capability to defeat the enhanced Dementors, so would it end up like feeding poison, creating a Dementor Boss in his Room of Requirement?
Something had to be done...
Watching both of them fall into thought, Harry hugged his knees quietly. Lupin's mention reminded him of that night two days ago—the constant onslaught of Dementors and Patronus Charms nearly drove him to madness. "Crying and laughing" described not his mood but his expression.
Would it have to be like that again?
The boy hugged his knees tighter in helplessness... Thinking about it this way, perhaps getting beaten wasn't that bad.
The pain of the flesh wouldn't drive him mad, at least.
"...How about a Boggart, if the Dementors have left a deep impression on Harry?"
After a brief silence, Lupin finally suggested a method, adding, "I left the one you lent me in the classroom. Didn't you say you have two? Although, there's a chance that Harry fears something else more..."
Lupin didn't finish, but William understood what he meant.
Harry might fear Voldemort more.
"Indeed."
Action speaks louder than words. William called Dobby to move the table containing the Boggart into the room. Once Harry was in position, William magically opened the drawer below the table, and a black shadow sprang out violently—
—but it wasn't a Dementor.
Watching the bald figure with a face growing on the back of its head, William couldn't help but frown—
"Why does this bugger look 3==D like this?"