Game Of Thrones spent the second episode of its final season prepping us for what promises to be the biggest battle in Game Of Thrones history. The characters almost painstakingly outline what's going to happen: civilians hide in the crypt, the White Walkers arrive, Bran (Isaac Hempstead Wright) goes to the Weirwood tree to lure the Night King into a trap — but, wait, where is the Night King? In the final shot of the episode, we see all the White Walkers lined up outside of Winterfell, and in the trailer for episode 3, Jon Snow (Kit Harington) says "the Night King is coming," but Reddit user jurkovsky thinks it might all be a trick.
Think about it: When was the last time a battle in Game Of Thrones went down explicitly how it appeared to be planned? In season 7, jurkovsky points out, Tyrion (Peter Dinklage) laid out the plan to take Casterly Rock, only for it to be revealed that it was all a ruse for the Lannisters to take over High Garden instead.
If the show is up to its old tricks, this could explain why we haven't seen the Night King or Viserion in any of the shots. Contrary to the plan, what if the Night King isn't going with the rest of the White Walkers to Winterfell, but taking Viserion to...King's Landing? Not only does this throw a wrench in the Starks' plan to use Bran to lure the Night King out into the open, but it would, as another user pointed out, be an easy way for the Night King to destroy the one thing the humans are fighting for: the throne.
If they're no longer unified in their fight for the throne, who's to say they'd remain unified against the White Walkers? In the Night King's frozen mind, that would leave the humans weak and unorganized...and ripe for the zombiefication.
Even if this isn't the case, there's some reason the show has been keeping the Night King hidden. It's either a hidden agenda or an attempt to not give me nightmares until it's absolutely necessary — but Game Of Thrones has never cared about giving me nightmares.