Played with Liofi.
For some reason, he went to attack the GO, which turned out to have 48 black dragons with GS, and they severely damaged my level 0 hero.
Couldn't find anything in the center, but eventually found the central treasure chest by going off-road.
The guard consisted of 1-4 fairies, and it seemed like it couldn't handle more than 2 units, but it turned out to be stronger, and the cows didn't trigger at all.

I lost because I didn't know the map layout. My opponent had weaker troops and a weaker hero, and I would have easily won if I had just focused on building up my second-tier units.