I wanted to color this: [link]
Mexico seems like a tsundere character(I love tsunderes! ^_^), but he's actually a lot like Philippines. Or rather, Philippines is a lot like him. Well, whatever. They influenced each other a lot during the Spanish colonial period.
Mexico = Nueva Espana
Feli = Felipinas or Philippines
Kuya = Big Brother. Its' use is not limited to family. A kind of honorific for guys old enough to be your big bro.
Philippine OC belongs to
Mexico OC belongs to
Hetalia belongs to