It was easier to handle lesser flying demons, which largely relied on physical or toxic attacks, but the bosses were different. The elemental attributes of a demon has nothing to do with its bloodline.
The monsters of the Neutral Continent were particularly peculiar. The bloodline could only determine the race, but it couldn't decide the future elemental attributes.
This was different on other continents. For example, the force in the bloodline of the family of Jungle Guardians was dominated by the formidable power of nature. If they learned this power, it was like divine intervention, but if they tried to learn something else, it would be rather difficult. That was the power of the bloodline.
Demons, and even all species on the Neutral Continent, had almost random attributes and nobody knew the personal attributes of each one.
Especially for those who had reached the boss-level, they could have additional elemental abilities for every level they increased.