Air defense had always been a headache.
In the Douluo I Star System.
Before Flight Soul Guidance Devices were developed.
During that era, the only people who could fly were Soul Masters with flight-type martial souls and Titled Douluo. This was also why flight-type Soul Masters often held the advantage in battle and found it easier to win.
As for why they were called flight-type martial souls rather than bird martial souls, it was because bird martial souls were only one part of flight-type martial souls.
Take Feng Xiaotian's Storm Twin-Headed Wolf.
It granted him the ability to fly.
So, was the Storm Twin-Headed Wolf a bird martial soul?
Obviously not.
There were also the Wind Sword Sect and the Sparrow Wasp Sect.
One had a weapon martial soul and could fly by controlling swords.
The other had a beast martial soul, but belonged to the insect category.
Neither had bird martial souls.
But did that stop them from soaring through the skies?
Obviously not.
There were also humanoid martial souls like Angels.
Even if angel martial souls were classified as beast martial souls under broad classifications, they clearly had nothing to do with bird martial souls.
Therefore, although bird martial souls made up a huge proportion of flight-type martial souls, the combined total of all other flight-type martial souls could still contend with them. Using only bird martial souls as a label would undoubtedly be an overgeneralization and a form of disrespect toward the other Soul Masters.
The approximate ratio was six to four.
In other words, bird martial souls accounted for sixty percent.
All other types of martial souls combined accounted for forty percent.
If they were broken down further.
Flight-type weapon martial souls like those of the Wind Sword Sect might not even account for one percent,