Kuurth without Cytorrak's enchantment was still powerful enough to beat the crap out of Colossusnaut. The only reason he got taken from the fight was that Colossus was unstoppable and making his runes collapse in on themself.
With it, he was unstoppable in every sense of the word. I never read Blackest Night though, so I don't know what Kal's capable of.
@KingD19
IMHO, Kal-L is more than capable of reproducing what Colossus did to Kuurth (forcing him backward to the source of his "rune path") and he would survive the explosion (unlike Kuurth who had to be tped away at the last instant by the Serpent).
I mean dual enchantment Kuurth survived an aircraft carrier being hurled at him, a powerful Siren backed Dazzler laser blast, a "disintegration" beam, having his blood ignited, being BFRed, and that living bomb attack with Gambit and that rock guy. Not for anything but regular ol' pre-flashpoint Superman can easily tank that stuff. Hell, Classic Juggernaut could survive that stuff (the only thing that would work would be the BFR).
Kal-L (without the BL ring) is like a pre Crisis Kryptonian power wise (or close to it). The Ring just makes him effectively unkillable (barring a weakness Kuurth is incapable of reproducing).
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..even the outer hells are indifferent matters for they bow only to potent and archaic Nodens.
I don't think he could force him back; not to that extent at least. Colossus clearly stated that Kuurth was stronger than him, but he had the Unstoppability enchantment.