Vecna in Stranger Things and Szass in Honor means that liches are overplayed. You say they didn't want to repeat a very successful Venca, but then you suggest they do a variation on the theme.

Go a different direction. D&D is still of iconic, unique villains. Tiamat is main stream enough to draw a following. Or just pick one of the other unique historic dragons and tell their story. People love dragons and having a dragon with a long history that you get to learn about would be fantastic....and open up a lot of artistic license for where to take the story. Klauth would be awesome. Super strong. Smart. Powerful magics. And a name people can pronounce (because let's face it, D&D had some that people can't).

Episode 1 starts in the present with him ruling over whatever area you want, but future episodes can go into how he got there. Previous heros he's overcome. Powerful relics he's collected. Any and all of those can be hooks to get the "new adventurers" set against him and create storyline after storyline.

And if successful, then you go on from there with a different persona. Maybe then you take a lich, but didn't tell the story with them as a lich. Tell the story of how they got to that point. THEN, if successful, you roll back into the next season with then as a lich, because now they are more than just a super strong dead guy. You"know" them. You have some understanding of them. And that draws people back

Why? Godzilla already went toe to toe with the Avengers in a 70s comic release. Didn't really end, but Godzilla took all they had and was still standing when it ended, so this isn't that strange an idea.

Yeah, I only made it through the finale through sheer determination. Awful.

The first episode played into the mech responding independently to protect the pilot, then there was never anything more revealed any that and eventually that entire plot line just was ignored.

It's one of those cult classics that becomes popular simply because it's so bad.