What exactly is this? Seems to be a mobile game, but is it a remake of Heroes 3, something just connected to it, does it also come to PC?

Heroes 3: Era of Chaos Trailer

Looks like it could be some sort of Chinese knockoff. I wouldn't put too much stock into it.

I doubt it.. Ubisoft threw out all the lore and world building the franchise had built as soon as they got ahold of the IP.. considering they don't seem to want to admit the setting they use instead is highly generic and not very interesting, I don't imagine they plan to restore the old one (and if they did, the middle of the Enroth arc would be an odd spot).. if they did though, I have a feeling they would have a hard time doing it justice without involving Jon Van Caneghem in some regard.. that was my first guess.. but that voice over sounded remarkably close to who NWC go to voice Catherine way back when.. I want to say it was Wendee Lee who originally voiced Catherine, but don't quote me on that..

Yes, that was also my thought. I was just curious. Could be mobile or a browser game.

Crappy art direction, but I would have been surprised if Ubisoft had outsourced it to some studio where actual artists worked.