Last i checked the Khan got fatigued fighting Mortarion, who's only a little above average as far as Primarch vs Primarch goes. And the Deathshroud practically ate the Keshig (Khan's honor-guard) for breakfast. In the very same novel of all things.

The other primarch mention separately, in their own novels, that Sanguinius is considered the most deadly despite his benign temperament. Losing to Horus above Terra shouldn't be counted against him, since big H was on Chaosteroids.

I'm not a blood angels fanboy and I've never collected them. Jus' sayin'.

And he's a little off from breaking Ka'Bandah's spine.

Which did indeed surely deserve a breaking.

Still going Fulgrim... He's killed other Primarchs...

But to be fair, they could distract him at a crucial moment with a mirror.

He killed one Primarch with the help of a Daemonblade. Hardly qualifies.

I wouldn't say Girlyman is alive...

Because he's worth it.

Again powered by chaosteriods and wileding deamon weapons.

And if Magnus had not not used all of his power to teleport his sons away and shed his mortal remains Russ too would have killed a primarch. Without chaos help.

And then there are the Purged and the forgotten. But that can only be theoroms

But Fulgrim... D=