"You... really do know a lot..." Even though Harry had long known that Grindelwald must know quite a bit about deities, he was still greatly astonished that the man even knew the name Left Hand of Chaos and Calamity.
"Ha, I can't speak for anything else, but when it comes to deities, there probably aren't many in this world who know more than I do," Grindelwald said, looking rather pleased with himself.
Harry thought for a moment, then asked tentatively, "Then do you know what this deity is called? The deity who gave me this left-hand ability?"
Harry was genuinely a little curious.
He had previously tried asking quite a few people about the Black Man, but without exception, none of those who knew anything about deities knew of the Black Man's existence.
They did not even know that deities could take human form.
And among them was Grindelwald's student, Professor Lockhart.
"Oh?" Harry's question seemed to take Grindelwald somewhat by surprise. "You don't know this deity's name?"
Harry shook his head.
"He actually granted you power when you didn't even know his name?" Grindelwald was even more surprised. "Such a thing actually happened? Hmm, tell me in detail, from the beginning."
Harry thought for a moment, unsure where to begin.
Only after quite a while did he tentatively start with the summer after his first year, when he had curiously used Magic Perception to see whether there were any other wizards in his neighborhood, and the Black Man had suddenly appeared before him.
Then he spoke of how the Black Man had also appeared in his soul world.
"No, no." Unexpectedly, Grindelwald shook his head repeatedly. "There was something before that. You must have done something before then that caught that fellow's attention, and only then did he appear