Killer Move of Intertwined Ice and Fire

Though Voldemort at the time was a veteran Demon King level wizard with profound magic, at his core, he was merely a madman whose soul had been split into seven pieces, made volatile and unstable by the loss of his soul!

Even Voldemort had been so difficult to kill, let alone Smirnov, who was still at the height of his powers?!

At this point, some might be wondering: if Demon King level wizards were so difficult to kill, then how had Grindelwald so easily killed Ares Craig, the president of the American Magical Congress? And why had Dumbledore and the others been able to kill Mechanical Soldier Number One through Number Four in succession?!

One had to know that, as a veteran Demon King level wizard, Grindelwald had advanced to that level over a century ago. He possessed nearly a hundred more years of experience as a Demon King level wizard than Ares.

After leaving Nurmengard, the hidden injuries and lingering ailments in Grindelwald's body had all healed under the effects of Linley's Nirvana Fire, whose healing properties were equivalent to Phoenix Tears. Aside from the irreversible wear of time, his body had returned to its peak condition.

Moreover, Grindelwald had relied on the combination of the Fiendfyre Curse and the Shield Charm to advance to the Demon King level—the Protego Diabolica he had created himself.

Both the Fiendfyre Curse and the Shield Charm were exceptionally profound magic, let alone their combined form, Protego Diabolica. Coupled with the advantage of being its creator, no one in the entire wizarding world had gone further than Grindelwald in the study of Protego Diabolica!

Now look at Ares Craig, president of the American Magical Congress?!

Ares had relied on nothing more than the Diffindo, a spell even some young wizards knew, to advance