So, Furuichi did get the 0th Seal (an equal instead of a subordinate ?). Well, everyone got the seal anyway ;p.
The move reminded me rather more of one of the attacks from Saint's Seya (especially the way the hands are held).
So the Demon King actually had a reason to destroy the Earth. It was in order to erase those humans that were using demons and the Demon Lord's family as playing things and tools in order to make profit...
I guess the Earth Plot is finished. Now there is still the Demon World plot that was going on, Black Beel, Saotome's back-story, or is it actually the end ?