Invisible character? Oof, that could be a lot of things, unfortunately, even a few dropped frames can occasionally lead to weird graphical glitches if they happen at a bad time... at what part of the game are you?
If you're in an outside area and you have a "Horn of Detrius" in your inventory try using that and see if that fixes it. Or if you can get to a bed try sleeping. both of those have calls that should reset your appearance.
Its all good now it kind of just fix it self, my guess it had something to do with the traveling using the portal. Like after you raze a town and can no longer use it, but choice to go there anyways, in this case it was the last town in the game. Right now replaying the game with the good guy end or what ever you like to call it. Also great game only wise there was more spells to damage with and of cores a longer game but other then that its really dam good. So if by chance you ever feel like making a squeal to the game I would like to help some how.
Oh dear, that does sound like a bit of a glitch indeed. That might actually be an oversight on my part (I didn't test the final stretch of the 'evil' route quite as well as I should. I'll definitely look into that!
As for a sequel, I want to do that (And I also want to remake this one in a better engine with more content and better graphics) but I simply don't have the time or budget for it anymore. If the ever changes in the future. Perhaps!