KindVonDerRitter in 218'
Kind Von Der Ritter is a man from the DarkHarvest00 ARG.
Though not much is know about him, it is known that he "worships" Slender Man as a god and has been driven insane by his obsession. However he's not a proxy since he merely worships the Slender Man but wishes to become one himself.
He has been following Chris and Alex since the very beginning of the series. He uploads strange and disturbed videos to his YouTube channel and appears to have the ability to travel through or control time. It is assumed that the bathrobed figure that Alex & Chris have seen on several occasions is the one uploading these videos, as shown by one of the videos, entitled 218.
As of "Daniel Shipman's Visits" series, it is suspected that KindVonDerRitter is Marc McComber.