Juana, most known as "Melli" represents the country Uruguay. She is called "Melli", because is a short way of "melliza": "not identical twin" in spanish. Because she shares many similarities with Diego.
She has the appearene of a 18 year old girl of short stature, futbol lover, kind of tomboyish with her clothes but still mantaining much of feminity.
With Diego (Argentina) she shows much of her weak side, for more that she tries to look strong before him.
That is a most pathological case; since he is her older cousin (Uruguay is the only blood related char of Diego), and formally she reffers to him as "Brother".
Since kids they protected each other, and Diego cared (and cares) for her very deeply. And that makes her really happy. Having a somewhat "cousin complex": to the point of to inspire her flag and its colors on his flag, to choose his same national flower, and to share even the festivity of the bicentenary with him.
Others countries look at her like an argentine province for to have made such things along her history. Diego found it really charming (becaus ehe has a really big ego, and that made it even bigger XD).
Joao (Brazil) since kids was crazy for her, bullying her when kids, and now taht tehya re older he still bullies her time to time, but knowing that he likes her.
Always jumping over her, hugging her and being clingy. He goes directly to teh point "I LIKE YOU, LETS BE TOGETHER". And taht makes her really unconfortable.
But deeply, she likes him. Even If she doesnt want to admit it; she gets really jealous to the girls that she sees with him and gets worried If some day he doesnt appears or doesnt jumps over her ike he usually does.
Melli is what in the fandome is called "uke" I guess... XD
Must be difficult to live between two "seme" not only bigger countries but with more power (Diego and Brazil).
Good for her that they both love her (each one in their own way), and will protect her always.