RE stands for Russian Empire has always been good with children, since most children AKA Colonies have horrible/abusive parents so they have took them in secretly. RE is kind, strong brave and loving. 

13 Colonies is quite a famous colony but he has an abusive father, British Empire. So he regularly meets RE to vent to and just talk and hang out with. 13 is kind, insecure, quiet but immature and playful when alone and comfortable. 13 also has a secret crush on RE.