No escaping the Labyrinth

[Metathron]

I defeated five of the seven forms of Haas and managed to get to Murok, where I fought a couple of quite strong orc armies, but did not stand a chance against the big orc hero, even though we are only one level apart (my hero is a level 28 warrior, his is 29). Maybe if I also got to have a gazillion army slots to fill instead of just the five, the orc hero would not be looking quite as smug.

So I've tried going back to the elf lands, but it looks like there's no going back through the Labyrinth - the locations just repeat themselves without end.

What's to be done in this situation? If there's really no going back, can the orc hero possibly be defeated? If yes, what's the optimal army?