I will protect them...
He is quiet and calm, never showing any emotion out of his eyes. Nevertheless, he is fiercely protective; not only of his own Guardians, but of the next generation, and of the living world in general.
He wears the ring of the Reaper, and he carries the Scythe of Death. He needs nothing more.
Three hundred years ago, he was the Reaper who created the other six Guardians. He has never passed beyond the Gates, and as such, he and his Guardians are still serving.