Board Thread:Community Announcements and Events/@comment-25356303-20161017204403/@comment-34710634-20161020192351

"ZeniMax is holding an in-game Halloween event called The Witchmother's Bargain for The Elder Scrolls Online, starting October 15th" *13th ;)

And I would rather say that it's a Witches' Festival event made a bit Halloween-ish. That holiday was in TES since Arena or Daggerfall.