I've seen so many birthdays for Hetalia characters that coincide with national holidays and occurances that I wanted to try this myself. I had to fill the void with other nations. And for other characters, I'll explain who they are at the end of this journal. This entry will be updated with more nations to come. Feel free to add your comments below and I'll try to answer as many questions as possible.
HOLY ROMAN EMPIRE
ITALY (ROMANO, VENEZIANO/CHIBITALIA)
HWF Master is a character I created for my project "Hetalia Wrestling Federation". He's a cross between Andre the Giant, Yokozuna and Bane of the Batman series. Basically, he's the embodiment of the world's wrath, hence why I put April 22 for his birthday, coinciding with Earth Day.
There is officially no Chechnya in Hetalia, but I decided to make one from the real anime. He's the one arrested for computer hacking in HBW Episode 8: "The Gentle Fight Between Russia and I". I'll try to think of a name that suits him best later on.
I couldn't find the exact date that Germania, Germany and Prussia's grandfather, was born, so I decided to use the date that East and West Germany reunited.
The Pictonians are aliens and don't have Earth days, so why did I put them having June 5 alongside Denmark? Because "Hetalia the Movie: Paint it White!" was released on that date. You could also call it "Pictonian Day" if you wish.
In the anime, there's an old man Japan was thinking of. He is the embodiment of the United Nations itself. October 24, 1945 is when the U.N. was established. Coincidentally, October 24 is also Hetalia Day. Squee! ^∀^
Many people have their own version of the Confederacy, or the Confederate States of America. April 12, 1861 was the beginning of the American Civil War.