The cursed scale part was just dumb, they could have just tested it on a animal, and she told them it was dangerous, the guard literally had to grab it like a thief because she would have avoided him, she doesn't want to hurt anyone.
Is even true that using the scale as proof was dumb in itself, the ony she could prove it was from a corrosive dragon was from someone touching it.
The new mage chief is a retard because he knew they had arrived on a small dragon but his rage against a commoner blinded him.
I'm guessing big dragons just don't show themselves much or mix with humans.
The original fiancee barely tried to help her but his brother was enjoying the coming slaughter, that guy should marry the sis and create a toxic relationship that ends with both parts dead.
I'm guessing that the sister will try something in the next chapter and Greed will punish her (finally).
In all honesty all of this would have been avoided if the mage just stayed in the kingdom and didn't force Greed to come out, he, the heroine and the dryad would life happy and calm days away from all the bad humans.