Forum adverts like this one are shown to any user who is not logged in. Join us by filling out a tiny 3 field form and you will get your own, free, dakka user account which gives a good range of benefits to you: No adverts like this in the forums anymore. Times and dates in your local timezone. Full tracking of what you have read so you can skip to your first unread post, easily see what has changed since you last logged in, and easily see what is new at a glance. Email notifications for threads you want to watch closely. Being a part of the oldest wargaming community on the net. If you are already a member then feel free to login now.

Dante. Hands down.

That is, if you only include as Astartes the space marines that remained loyal forever. And Adeptus Astartes are defined by their loyalty and service to the Imperium.

If you include non-Astartes space marines (as in: humans augmented in this certain way, loyalties be damned) then it would have to be Erebus. While he was most likely just a puppet, he was in a pivotal position, all things considered.

Of course, the only thing that really matters if how well the Astartes work as a whole. There's bound to be peaks but they don't matter that much in the grand scheme of things.

Zahariel El'Zurias. Either he's Cypher and has been travelling through time for 10,000 years fixing the timeline so that humanity isn't wiped out, or he was the original Cypher and set everything into motion that the subsequent Cyphers would keep upholding his legacy. Also he was almost one of the founding members of the Grey Knights. Seems pretty cool to me.

Sharrowkyn sniped a primarch. I still see no reason not to have him be the greatest.