User blog comment:DirgeOfCerberus111/Adeptus Custodes Vs. Grey Knights/@comment-2253300-20111028201241/@comment-79.193.1.205-20150326191510

That doesnt mean mouch, because it has to do with martial skill. A Gk could never match a great daemon in physical or martial ways, they are trained to destroy and withsand them on a psycological level, even their names are a scourge to daemons. As single combatants, they could never match custodians, they are not engineered for such things. One thing few ever take into account is, that there has been a case in the past, where the Custodians faced  something that was physicly superior to Astartes. the thunderwarriors. After the Unification wars, the Emperror came to the conclusion, that the thunder warriors - though the best offensive force ever created- simply where unable to live in peace. The where far more powerul than todays Astartes but their Minds were still Human and they where nothing but killing machines. So the Emperror comanded the culling of all Thunderwarriors. There were hundereds of Thousands of them and they were wiped out in a couple od weeks, without anyone noticing where they went. Officialy the Last thnderwarrior died heroicly in the last battle of the unificationwars. In fact Constantin Valdor and His legio Custodes are very likely to have killed them all, there wa simply no one else, who could have carried out the culling. the Neo astartes where simply to few at the time and also inferior to the Proto Astartes, concerning combat. Hundreds of Thousands, the best of the best, gone without a trace. Thats what the Custdians do with Astartes and the likes of them.