By Two Courts

Kaos himself is physically frail to the point of not being able to speak, while Den is a violent, red-eyed manifestation of all his rage. Kaos's father installs a transceiver in his son so that Den can actually project to a cyborg body elsewhere, and hence Kaos knows nothing of Den but the reverse is quite the contrary. It's uncertain if his father (spoiler) helped to start it off, but due to his rather bad habits it's certainly likely... and he was fascinated with his son being a multiple and even praised his level of 'mental adaptability', I think. Maybe that's a misquote. Ends up with a sort of semi-integration, and mental death of Den. Den is, once more, a big ol' villain.