Republic of Li'solaniEdit
He was his uncle and they had been together since Amadeo was a little child. The two were always seen together throughout the series and seemed to be very close. They seemed to work well together and Roni appeared to admire his nephew for his abilities. He also complimented him and flattered him for being able to determine the winds, making it very likely that he played a part in Amadeo's future arrogant and confident personality.
When he protected him from the arrows sent from Donatello's fleet and died from his wounds, it appeared as if Amadeo grieved his death. The two seemed to care for the other very much.
To say that he admired the Doge of Li'solani would be a lie but he certainly respected him. Amadeo seemed to be aware of that he was two-faced but that he believed that he was at least genuine towards his own people. When he met them on the Centro Seas, he was relieved and claimed that they were in luck. However, when Donatello ordered that his soldiers attacked them, Amadeo's relief was traded with anger.
He cursed him and called him a traitor, visibly shocked by Donatello's actions. When he has been wounded by an arrow, his anger seems to have faded, traded with grief for his uncle and disappointment in the Doge of Li'solani.
Republic of VenedikEdit
Not much is known about their relationship during the naval battle but it is clear that Gino had left them twelve years ago to serve Venedik, which must have been an act of treason in Amadeo's eyes. Roni claimed that Gino left because he was jealous of Amadeo's abilities but that accusation is never confirmed. That being said, they seemed to be on very good terms when they were younger and Amadeo's abilities first started to show.
It's likely that Amadeo's hate for him has been fuelled by Gino's betrayal, as his uncle appeared to be very loyal towards the Queen of Centro. That being said, Amadeo is shown to have a very hostile opinion of Antonio and repeatedly criticises him and his actions.