Of course, I mean within reason. I don't expect anyone to fight a dragon and live to tell about it, get lit on fire and not have third and fourth degree burns, or even wear armor at all (because armor is heavy). Of course no one's going to check if you really are like the character, and hell, if someone wants to make an argonian or khajit based on them, that's pretty cool, I guess. What I mean by "no mary sue" is that, well, don't make yourself perfect. Nothing too crazy, like all three words of five shouts, 100% resistance to shock or ice, being masterful of all kinds of magic, etc. Somewhat realistic for a fantasy game (a bit of a paradox). Things that are pretty reasonable, like if you can take the cold and wear shorts in the dead of the winter, in 30 degrees, maybe some resistance to frost.