Although it doesn't say so, Kardur, Doomscourge goads the table upon his entering the battlefield. I don't need to tell other Commander players how fun Goading your opponents is. Naturally, this deck wants Kardur to hit the battlefield over and over. Rather than have him ever visit the Command Zone once he leaves, we're going to get him into combat, let him die, and reanimate him over and over. And if attacking with him proves too difficult because all of our opponents' creatures are tapped from all that goading, we'll have ways to sacrifice him to keep things rolling.