I like the idea. If the players respect the potential behind it and create a real myth/background for their characters this way, it may add a whole lot to the game. Of course, I am hesitant about players who would simply use the feature to build a stupid divination of their character that does not reflect the truth or sides of it at-all.
Perhaps it would be a good idea if you can edit your reputation ONLY in lower levels or in the very first IC years of your character.
There's two reasons for this suggestion:
1. The need for a character-built reputation can serve for the character's background, so it would be handy especially for things regarding the character before getting really known in the game, like ie: Elf Bigname was raised by a poor family, although there is rumor that his mother has also come in close contact with humans. But as long as someone starts interacting in the game, he does "build" his reputation anyhow, and that is indeed the REAL reputation he creates on the realms.
2. It would avoid cases in which someone might wanna scribe a myth about himself that does not reflect the reality of his character. For example, someone who eventually turns out to be a horrible wimp, running away from fights like a coward and everyone in the realms think he's an joke, should not be able to scribe a reputation that "the people think he is a mighty warrior, although he often has to break lose of his position for strategic reason".
Just my two cents (or a bit more
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