Implementing hero transfer in campaigns.

So, I had a question. How is the transfer of heroes between missions in the developers' campaigns implemented? Level, stats, spells, skills, and abilities are transferred. I found the artifact transfer in the .lua scripts of each mission's addon. But what about heroes? And is it possible to do this between campaigns, for example, between the campaigns of the first game and the Hammers of Fate addon with Raileigh, considering that all campaigns are installed in ToE with a modification? I would be grateful for any explanations.

Everything works thanks to the xdb files of the campaigns, within which, in certain tags, they indicate from where and to where the hero should be transferred. And transferring between campaigns can also be implemented; one tag is allocated for this (this is exactly how all the main characters are transferred in version 1.6). If desired, it is quite possible to arrange a transfer between the Hammers of Fate and The Price of Loyalty campaigns; the main thing is that the script names of the heroes match during the transfer (because there are two Raileighs, Isabels, and Freeds).