眠らせ姫からの贈り物 (Nemurase Hime Kara no Okurimono)

Background
Now, go to sleep One of the tracks of Akuno-P's of Seven Deadly Sins series. At the end of the PV, a dialogue between Elluka Clockworker and Gumilia is shown, hinting the relationship of Margarita and Julia with Père Noël.