Inferno tactics.

Ah, a minimum Dragon Utopia ... Then that's clear. 10 demons from spearmen. You had 21 dogs. That's another 15 demons. Now imps. 61 + some amount with the hero. Let's say together it will be 105. That's another 3 demons. So far that's 28. Gogs. You have 33 of them + possibly whoever came with heroes. From this, you can make 12 demons. Well, 14 let's say.
In total, it comes to 42 demons. I counted the external dwellings of gogs and dogs, as you can see. Fine, probably not all 66 were slaughtered. Probably bought another 8 pieces. Well, in general, it almost worked out ...