He is often described as being much more like his father as he has light blue fur which is also plain blue fur like Alejandro's. Unlike the other older boys Oscar's clothing is more laid back much like Lucie's clothing even though she is not associated with the Junta however it is relatively serious. In this case he wears black trousers, a black T-Shirt and a black leather jacket.
Though Oscar is friendly with the older children he is shown to be particularly close to the Paraguayan vixen Graciela and the Chilean vixen Jacqueline, he is also close to the older Junta boys until the Hypnotist puts them under his influence and turns his friends against him. He is often regarded as the most serious child in the Junta because even though Miroslav is serious at least he has a healthy sense of humour and even though Luiz has a sense of humour it is very dry and cynical but nonetheless Oscar has some enjoyment in it because of Luiz's satirical humour almost.
Even though many of the older Junta boys such as Miroslav, Artashes, Nikolay, Alfred and Alexander are in relationships he acknowledges this but even so he appreciates the beauty of the Colombian vixen Carola and is just as close to her as Graciela and Jacqueline, compared to most older children he has a relatively bad temper but he has a very good job at hiding it but seeing as he is from one of the world's most violent countries he has a relatively violent streak as well, like Luiz he disapproves of "American" humour which shows a great amount of hypocrisy in him seeing as Guatemala is in Central America but there are some things he can see the humorous side in. His temper also leads to a great, great frustration with the Junta babies at night mostly Santiago but sometimes Josefina who is also very babyish often saying "And I thought Uruguay was a peaceful country" however it also puts a great strain on his relationship with Vladimiro and Vytautus. But nonetheless he does respect the older Junta children and is good with the Junta babies and the younger Junta children.