It’s pretty much along the lines of what you’re talking about here.

Nintendo did brilliantly with the twin GBA games, Oracle of Seasons and Oracle of Ages. Both games had an intertwined storyline, and in each game you could find secret passcodes and such that would only work to unlock items or areas in the OTHER game. You could play either game separately or you could play both of them concurrently, going back and forth between them as you found neat stuff in one or the other. In order to get the final ultimate ending, I think you had to beat both games normally, and then play either of the two AGAIN with the code from the ending of the other in order to face a new final final boss.

The Suikoden series have looked for save game data from the previous game since their first sequel. If you have a previous save it gives you access to secret areas or characters, generally with an additional bonus if you beat the previous game with the best ending (i.e. finding all 108 characters).

Monster Rancher 2 gave you some special monsters if you inserted game discs from other games by the same developer.

Going back further, some of the old SSI D&D games let you import your characters from previous games (e.g. Hillsfar let you roll characters from scratch, OR use your party from Pool of Radiance, or something like that.)

The Ratchet & Clank series of games also gives you access to discounted weapons and secret areas if you have a save file from a previous game in the series.

I’m sure there are other games along these lines, where the developers include something a little extra for you if you’re a repeat customer.

I realize that’s not exactly what you asked for, but it is a step in that direction.

I’d imagine actual importing of characters across games would be exceedingly rare, because it requires:
* A single developer to live long enough to make multiple games (in multiple franchises, not just one game and its sequels);
* The developer creates this “universal” system from their earliest game so that it is both forward- and backwards- compatible. The intent must be there from day 1.

This combination of foresight and longevity is… not normal in our industry :)

“…no, no, this one looks normal.

“…no, he doesn’t look like one of those orc things like last time. And he’s not some kind of embodiment of a tank. He’s got on a kind of skirt and a little white helment.

“Hold on! He’s doing something! He’s…

“Sir, he is planting flax at us. … Yes, aggressively. … Yes, sir, I suppose I could shoot him, but he doesn’t seem to be much of a threat, and we could really use some linen.”

…or maybe ATITD characters would import as some kind of weird crafting types. Or maybe it could depend on their rank. Master of Worship? You’re a cleric (or healer of some sort)! Sage of Art & Music? Bard or entertainer! Student of Body? A low-level Ranger! Pharaoh’s Oracle of Architecture? Uh.

Unfortunately the character models in the IP that I’m trying launch with the help of our ebullient friend here functions on a mostly “level” system, there isn’t a progressive model of advancement, because its not really a standard RPG, the differences between the characters are the point.

I bet you could make some parrallels between the ludic contiguity you’re discussing and episodic content, particularly in a drama game.

Balancing factors can deal with that somewhat, but another measure should be taken somewhere.