In my (limited) understanding, Cyrus WAS the HoonDing. That is, he's not CURRENTLY the HoonDing, and I use http://www.imperial-library.info/obscure_text/viveccyrus.shtml as a reference:
"The young ansu dropped his stance. 'He cannot be beaten,' he told Cyrus, 'We know every sword move created in history, and none of them would avail you, even if you learned them from our memories-in-stone, which we would be obliged to lend you if you asked. You killed the white king in the Hammerfell, after all.'
'What?' Cyrus said. 'The Emperor? I didn't kill him.'
'Of course you did; you were the Hoon Ding.'"
But later in the pasage they refer to him as the Hoon Ding,
We are telling to Hoon Ding to run
Another idea, Pankratosword cuts the "Atmos," right? so maybe it splits atoms, which would release the weak and strong atomic forces, and then create a massive blast: like an atom bomb. If enough atom bombs hit an island, it could sink, right? So Pankratosword could* in theory be a way to split atoms with your sword.
*Just an ideea. i don't strongly believe this at all: it's more modern and scientific and less magical, and Tamriel has a tendency of leaning toward magic.