Last Immortal game I played was as Korea on an OCC (2nd immortal game, won turn 310 Spaceship. YAY!!!). Other civs were Russia, Austria, China, Byzantium, Germany, Songhai and some other guy I forget cuz he got eradicated quite early. Started smack dab in the middle of the Pangaea with no Aluminum on sight (as I found out after I researched Electricity).
Theodora was the earth's Bestest Best Friend in the WHOLE WIDE WORLD. A DOF with them secured Friendly relations with pretty much everyone else (Girl gets around quite a bit, I presume), even if people were giving signs of being a little stabby-stabby.
Come Industrial, she declared war on me. Apparently for kicks since she did it when Germany was just "feigning friendship" with me, hoping that his Landsknecht carpet can take me over. 5 Crossbows were enough to repel his attack. Germany will continue to do this until the end of them game (I bribe Austria a paltry 78 Gold to war with him. Nukes went flying).
Eventually, Theodora was swallowed up by Cathy, Wu by Napoleon (this was long overdue, Germany captured Beijing a thousand years ago), Askia by Cathy again and part of Bismarck's lands by Maria Theresa. Interesting to note that by the time the game ended, only 4 CSes were left. Everything else were either conquered and not Liberated, and all the rest were Married (Austria had a massive 800 GPT at one point). My tiny nation of Seoul was the only thing separating Maria Theresa and Cathy, who were sworn enemies who were BOTH gamelong friends of mine.
Some constants:
Cathy seems to do well in every game I see her in. She'll amass a ridiculous amount of land and will seem to conquer a lot when left alone. Maria Theresa, well, that's the first time I saw her get ridiculous. I was playing a Maya game a while back and when she conquered a CS pre-turn 100, I came in and puppeted both her cities (the CS and her cap.) Theodora tends to stay small (like playing a proper 4-city Tradition opener) provided she doesn't get conquered.