I am making a little Bionicle rewrite where everything is a bit more edgy, just how I like it! Maybe the events don't change much. I like to focuse on the innerworkings of the characters and motivations.
You can hear this Matoran approach. Kongu is the largest and heaviest of all Le-Matoran. And also, the most serious of them all. Even more serious than the one and only Turaga Matau... but he wasn't very serious to begin with. Clumsy around the top of the trees and always struggling with things other Le-Matoran find second nature.
Regarded as the right hand of the Turaga, she (I change the gender of many characters. Working with mostly men is a bit boring. Specially character-design wise) has been by his side since the very begging of their lifes in Mata-Nui. Turaga Matau had seen her aptitud, her spirit, her unyielding compromise, and took her right away, right when her first tattoos were being carved into her armor.
Turaga Matau is a very colorful individual. Painted from mask to feet in markings of all kind, so it was normal to get condecorated with them instead of badges like in Ta-Koro. Something permanent, something that jumped to you the moment you saw them, no matter the circumstances. Kongu ofter refused many of them, since she never think she did a job good enough to earn them. A perfectionist. An addict to her Duty, just like a good Po-Matoran.
She was the first to ride Gukko. Trained the others to do as well. Always blaming herself of the losses of those days because she didn't think of one crucial detail: They weren't the only ones in the sky, and they weren't the ones on the top of the food chain. The predators of the Gukko began a hunting game. Take the colorful rider away instead of the Gukko bird. If one Matoran was taken, surely more would come, ending in a massacre of one side or another.
This event inspired her to create the capes. The other Le-Matoran of the Gukko Force had them implemented in their seats meanwhile Kongu has it on her at all times. Sometimes she uses it for gliding and help her close gaps between jumps.
She formed the Gukko Force, and trained the army of Le-Koro. Kongu always says that Turaga Matau ordered her to do so, but that is a lie. She likes to use that as an excuse in recent years, seen how the other Le-Matoran only see her as a general, someone who barks orders and puts you to work even when it's your resting days, to try and get some criticism off her back... it's not working at all. Feeling more isolated.
That also made her stand out. Her posture, heaviness, and ruthless attitude was made a mockery between the Le-Matoran, who are more... laid back. Taking it specially from Turaga Matau. And when Toa Lewa came along and had the same laid back attitude, it made her feel even more self councious about her body and aptitudes, sometimes forcing herself (and other) to be even more exceptional. To "make it up for being made wrong by Mata-Nui" she sometimes thinks at her lowest.
Maybe she won't get too much character development in the island,(a butterfly-shape on her clothes to signify she wants to bloom more than anything and change into a flying creature) maybe even less back at Metru-Nui. But I'm sure Kongu would feel very very strongly about being denied the Kanohi Kadin.
Last note: the little rings on the cape are a nod to her old design, where she would hook to the Gukko birds with a series of hooks to not fall off in the more dangerous maneuvers