Could you please advise on how to defeat those large enemies riding elephants? As soon as I gather an army and sail to the mainland, someone appears from the other side and starts wreaking havoc on my island. It's impossible to defeat them with Isabella, and I don't have enough money for two armies. I have to return and try to defend myself, but it usually doesn't work. They are tough.
And they have incredible luck; only black birds appear for my troops.
Maybe someone can suggest an algorithm; I've replayed it four times, and I'm getting tired of it.
(these are my first heroes)

update
In short, the main thing is not to hesitate. I quickly gathered Marvel and all the troops that were nearby and sailed to the mainland. I defeated everyone there, placed a mercenary with an army near the portal, and Marvel went to the western continent and brought order there. I gathered dragons, and that was it.