In the twilight.

Has anyone managed to complete the scenario playing as the Hero?

Yeah... and the losses were only in the final battle with the demon, and even then, just a dozen zombies and three elementals. In the last battle, you can fight with all the units you've acquired throughout the game; I left the Haven troops in the mine. So, the last battle as the Hero turned into a massacre. Level 33. Also: the resurrection scroll wasn't really needed (I found resurrection and shock spells in the mages' treasure). You can also use summoning magic (the spells are available).
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P.S. I liked the map. Thanks to the author!