If weird things keep happening to me in this game, I’m going to start getting a reputation.

So I start the game over, because now a week and a half in-thanks to several of your replies-I now have a much better idea of what heroes I want, what skills, spells...etc. And it paid off. I finish ‘Homecoming’ with Christian having the following numbers: Attack: 14, Defense: 8. I have a Cleric with Expert level “Chain Lightning”...and overall very pleased with everything. LET’S GO BOYS!

So I save the game and start the second mission, “Guardian Angels”. I proudly check my heroes’ stats, but now to my horror, Christian’s number have been lowered to Att: 11, and Def. 5. What the hell? I reloaded my save file several times with the same results.

So here’s my obvious question: Is this a bug, or is this some sort of cap like the level 6 hero cap?

Either way, with all the strategy guides andI posts that I’ve read through, not one word about it. This game is startin’ to get on my nerves!

The "Special Rules" note on http://www.heroesofmightandmagic.com/heroes3/campaignqueen1.shtml says that the heroes move on without their armies or inventory. I assume (perhaps incorrectly; I've never played this campaign) that this means none of the artifacts come through, even those actively equipped on the hero. If so, and your hero was wielding an item that provided +3 attack, +3 defense at the end of the first mission, then when he lost that item at the start of the second mission, he would have the statistics you report. Open the hero page and inspect the paper doll equipment page in both missions. Check whether you lost artifacts, and if so, whether their loss would explain the difference.

Exactly this.

It should also be noted on some campaign maps that the game only saves the level of the character, not their stats and skills and whatnot. I think its in the SOD campaign, but It's been a long time.

Yeah, that is an SOD issue, and I think only an issue when crossing campaigns (not as sure about this second point). The heroes transfer just fine in RoE and AB.

As for the OP: I agree with the others. Check your map 1 artifacts.

Yes. Heroes transfer correctly in SOD too, but only between levels in same campaign.
The engine didn't allow for any transfer between campaigns. Perhaps they meant to introduce it in SOD, but the fact remains that the SOD expansion was released before this functionality was added, but the text telling you about the inter-campaign transfer unfortunately remained.