How much power does a DM have over what goes on a Character Sheet?
ForeverDM here, running the final levels (currently lvl 18) of a nearly-four-year nautical 3.5 campaign. Heavily based on Savage Tide, the campaign path that was Dungeon Magazine's swan song. The party is now at the point where they're paying planehopping visits to the (homebrewed) pantheon, trying to recruit the gods themselves into an alliance to go punch the goddess of the elves until her alignment changes back to Good.
They have commitments from the triumvirate of not!Aztec gods, one of whom is the local LE bat-faced god of volcanoes, fire, and death (important later). On their way to sign up the CG mermaid goddess, they took a planehopping wrong turn and wound up in the realm of ENTROPA, the Evil goddess of temptation, memory, fate, and time. Here, something happened that is splitting the players IRL.
Party:
-the Swashbuckler: Errol Flynn with a chip on his shoulder. Captain of the party's naval fleet, hunts down and murders pirates.
-the Cable: comes from a dark alt-future where the elf goddess' plans succeeded. Fell from grace, cut a deal with Entropa (the kind of deal that gets worse all the time), and was thereby hurled back into the past so he could try to change the future.
-the Robot: warforged champion of the not!Aztecs, laid dormant for millenia until the party found & activated him.
-the Grouch: Dour & pessimistic nautical type, he converted to worship the not!Aztecs' Good couatl/phoenix goddess after a reincarnation experience.
-the Gnome: carefree, sprightly druid whose will has a core of steel, she follows the hardassed LN god Neptune.