Searches of the lost city

As per the Seer's request, the exchange is not for a statue, but for a Horn of Plenty.

Technically, yes, but to get the Horn, you need to give the Guardian the Statue!

Regarding the scroll... I didn't place any dragons to guard it; that's a mistake.

Whose mistake? If it's yours, fix it!
By the way, the Turquoise (=Gray) one doesn't want to level up with dragons, as you intended – is he just lazy...? :)

Moving on. The Guardian (yet another one; surely not the last :)) requires an Angel Alliance. Ha! If I had one, would I give it to some random GUARDIAN? :)
Another minor point (compared to the previous ones). The inscription on the sign says (from memory): "To the east, there is a Seer who can help." I'm not a local, of course :), but one Seer lives west of that place, and another lives south.

Added 5 minutes later

I finished it in about 4 hours, played on 130% difficulty, just killed everyone, didn't find the Grail, the map is cool and not stressful.

It would be interesting to hear how you completed it? Did you study the map? Did you cheat? ;) Although on 130% difficulty, it's probably easier. I'm playing on Impossible, as the author intended. It's not easy!.. :)
And who else has finished it? Let us know!