» Thu May 17, 2012 1:00 am
The Gray Fox is the person wearing Nocturnal's Cowl, no matter who that is. The moment they put on the Cowl, everybody fails to remember that someone else was standing there just a minute ago, and the moment they take it off, everyone gets confused and asks themselves where the Gray Fox went. If you tell someone your name while wearing the Cowl, all they hear is "I am the Gray Fox".
The person who was the Gray Fox at the start of the Thieves' Guild questline - the once-Count of Anvil - has long since died, unless something very odd happened to him. At any rate, he ceased to be the Fox when he broke the curse on the cowl (which took the identity of anyone who wore the Cowl permanently, and not just while they wore the Cowl) and passed it on to the next wearer. He was, in fact, very glad to be rid of it. He wanted nothing more than to return to a normal life with his beloved wife, who was quite adamant about him quitting his thieving.
The person who was the Gray Fox at the end of the Thieves' Guild questline - who, depending on your playthrough, may also be the Champion of Cyrodiil and/or the Madgod - has also long since died, unless they became the Madgod, in which case they long since passed on to managing concerns outside of Nirn.
In any event, the Cowl may or may not have been passed as an heirloom of the Thieves' Guild to each successive guildmaster. It's also possible that some guildmaster, not necessarily the Champion of Cyrodiil, at some point went a bit batty and buried the thing in the Jeralls, where the Dragonborn might later find it. If you make a Gray Fox mod, you have some leeway there; you just have to keep in mind what things may or may not have happened, and make some plan that works with those possibilities.
However, the "Robin Hood" figure you're thinking of, the person who once was the Gray Fox, is not in play. There could be someone else like him, but he himself is long dead. Find someone else to play the part, or be prepared with a whopper of a good excuse.
I'll add this: I never got the impression that the Cyrodiil Thieves' Guild left the poor alone out of noble impulses. I thought they did it out of self-preservation. The Thieves' Guild had to be somewhere, and sooner or later outsiders would know where that was; whoever knew it had to willing to hide the Guild. So they set up shop in the scummiest neighborhood there was, and payed out lightweight bribes when the neighbors needed help more than usual. The bribes were cheap, because the neighbors were poor. Anyone who cooperated was protected, while anyone who tried to inform got framed themselves. So yeah... Thieves' Guild does not equal Robin Hood's Merry Men.