Corgatha: I've been playing the Homm 3 SoD campaigns, and have just gotten to the Unholy Alliance one, after beating Yog's Crag Hack's Gem's, Gelu's, and Sandro's initial ones. In each instance I was promised that the hero would transfer over his experience, spells, skills, and stats to the next campaigns.

I just started the Yog mission for the 6th campaign, and lo and behold, he is not the dude I built. I have (in part because I remember playing these campaigns a long long time ago, and while I didn't consciously remember, I had a bit of a premonition of trouble along these lines).

Does anyone know of a way to edit or alter or somehow make the game transfer over the heroes I spent quite a bit of time building? I do have the appropriate stats to use an editor for if that becomes necessary.

ZFR: Unfortunately, HoMM3 engine did not implement hero carryover between campaigns, even though SoD's campaign description does mention they do transfer. By the looks of it's something the developers wanted to add, but ultimately did not, and forgot to edit out the campaign descriptions.

Your choices are:
_Leave them as they are. I'd seriously recommend to at least consider this. I know some skill selections suck, but consider playing with poorer heroes as an extra challenge. Ultimately it's not something that will make or break your campaign.
_If you insist on editing, here is a detailed guide of changing those values in memory:
https://www.gamefaqs.com/pc/63965-heroes-of-might-and-magic-iii/faqs/25014
or
https://www.gamefaqs.com/pc/63965-heroes-of-might-and-magic-iii/faqs/25014
As far as I know, there isn't any dedicated save editor.

Corgatha: And it's not about the challenge; hell, Yog will probably be weaker than before if I can get these edits to work (no magic). But it's grating to have a campaign hinge around hero building like this and to just have it all thrown out the window.