Koala

Koala is a former slave who was set free by Fisher Tiger's rampage on Mariejois. She sailed along with the Sun Pirates to reach her home town. At some point later, she became the Fishman Karate assistant instructor of the Revolutionary Army, where she now works with Sabo, making an appearance in the Dressrosa Arc. Aladdin described Koala as having the lifestyle of a slave ingrained in her blood. Even after being set free for three years, she was very apologetic and vowed to never cry or stop working. The pirate explained that if a slave ever cried or stopped cleaning, then they would be killed. Koala seemed to consider the Sun Pirates her masters, as she asked them if she would be killed if she stopped cleaning.

The pirate also said that slaves panicked constantly, even when they were by themselves, and could never trust anyone. It is unknown if Koala also became paranoid in that regard. But when Fisher Tiger convinced her that they were not like the Celestial Dragons by throwing a gun into the water, she finally cried for the first time in years. She then began to regard the Sun Pirates as her family rather than her masters, though this did not stop her habit of cleaning even when she wasn't asked. By the time they reached her home town she genuinely liked the fishmen and mermen of the Sun Pirates, creating especially strong bonds with Hatchan and the future members of the Macro Pirates. She went as far as to actually hold Fisher Tiger's hands despite him trying to shake her off. At the age of 23 Koala has become much more mature, having shown compassion to Sabo for not being there to save Ace and that he should not let his guilt get to him. She also has become rather playful and cheery, having gleefully hugged Robin again after meeting her and teased Sabo about him crying upon meeting Luffy again. She has also been shown to have a temper, as she got angry with Sabo for fighting Fujitora instead of staying at his post and comically pinched his cheeks for his disregard for his duties as a Revolutionary. She's been shown to have certain skills like being able to take down larger enemies and great agility and can make a big jump from the stands to all the way down to an underground port while bringing Sabo clothes to wear. Their position indicates that in terms of combat is above simple revolutionary soldiers, so as to have a decent level within fishmen standards despite being human. She is skilled enough at Fishman Karate to be able to teach it and was able to defeat an opponent much larger than her. Not being a fishwoman and still being able to learn the art makes her more impressive. In the anime, she is shown to be proficient enough to defeat a group of five armed men with only a single strike each.