The pirate fleets are marauding groups of people who do not scavenge for themselves, but rather raid other scavenger fleets for supplies. Unlike the other fleets, pirates use intimidation and often violence to get what they want.
Intimidation Vs Deterrent
According to what Bellows had told to Ledo and Chamber, there exists a balance in which human lives are not recklessly taken, and the usage of weapons is considered as a last resort. The side with the stronger force is normally the victor and negotiation through deterrent is seen as the best means of defense.
However, this balance is not without its flaws, as pirates often do not follow these unspoken rules, considering the frequency of their raids and their willingness to spill blood. The idea of showing the pirates that it is not profitable to raid a fleet cannot be backed up without sufficient force, and often the raiders get away with what they want.
The pirate bands have no set rules in terms of organization, and many will simply join up with each other in temporary alliances to raid a mutual prey. Basically they are nothing more than looters who steal from those who are weaker than they are, and use intimidation to cow others into submission. The fleet led by Pirate Queen Yukkage is considered the most powerful and many follow her lead if required. However, if the opponent gains the upper hand or proves to be too difficult to overcome, the pirates will not hesitate to retreat and abandon their allies in order to save themselves.
Shift in the Balance of Power
With the arrival of Ledo and Chamber, the Gargantia and its allied fleets now have a tremendous advantage over the pirates. With Chamber fully capable of repelling or even destroying the pirates completely, the marauders now find themselves far behind their intended prey in terms of technology. Even the combined forces of Yukkage proved to be ineffective against a single Machine Caliber. Currently, the pirates now must find a means to counter this huge gap in military strength.