Warlock – “Raelag’s Offer” [Campaign 4, Mission 5]

I saw a walkthrough of the entire campaign, even with a cultist hero and no magic, so it's definitely possible. I personally didn't even try to repeat it. And in this mission, if you don't get distracted by other heroes/cities/garrisons, the warrior shouldn't have any major problems.

Well, if you rush straight to the end of the map to Isabel, then of course there's nothing impossible about it, but it's not as interesting to me. What's the point of playing the campaign if you're just trying to rush from one scenario to the next? Well... of course, it's a matter of taste; some people probably enjoy speedruns, but I like to explore the entire map, max out my hero, and, of course, give the annoying AI a good beating.