Meet My Teacher, Grindelwald

The old man and the young man traded insults without mercy for a while, ending with Sean's defeat.

That old bastard really hits hard... Sean thought as he rubbed his stiff shoulder.

An argument was just an argument—why did he have to use some powerful magic he had invented himself? No sense of fair play at all...

Across from him, Grindelwald opened his mouth and exhaled a cloud of blood-red mist. "You little brat with no sense of fair play—you actually used the Boiling Blood Curse on your teacher?"

"It didn't affect you anyway," Sean said through gritted teeth.

The two glared at each other for a while before each lazily leaned back against the chimney.

Christmas snowflakes settled on their shoulders, and neither of them used a spell.

Grindelwald looked at the bright moon in the distance, his tone unhurried. "This is probably the last peaceful Christmas."

Sean turned his head slightly. "You found something?"

"According to my recent investigation, Herpo has already begun gathering an army."

"Gathering an army..." Sean silently turned the phrase over in his mind, then asked with some confusion, "I've always wondered: what form does Herpo's army take in the real world? Dementors, Silent Mouths, Half-Ghosts capable of casting spells?"

Grindelwald conjured a cup of hot mulled wine from thin air. He took a sip and gently swirled the goblet as he spoke. "The specifics are still unclear, but the things you mentioned will certainly be part of it... But those aren't the key. The key is those old acquaintances who retain their own memories, their own spells, their own feelings, yet will still become our enemies..."

Grindelwald's voice was light, but even the falling snow seemed to intensify.

Sean fell silent. He knew what the other man meant.

Herpo possessed the ability to