This is really creepy, I warn you, it also deals with a subject that is sensitive to some (IE: the plague, black death, loss of loved ones.) It has partial genderbending (Arthur's late wife Francine, is evidently France.) It also has character death, so read at your own risk.
I Don't Own Hetalia, And I Certainly Don't Own Black Death...
Arthur sat alone. The Black Death had taken all he ever loved. It had first taken his older brothers, one by one. Then it moved onto his older sister, soon after, it took his wife, Francine. It proceeded to take his youngest son, Matthew, and the lad's brother Alfred right after him. And soon, very soon, it would take Arthur himself. This was a fate he could not escape, instead he embraced it. He even made up a little rhyme, so people in the future would not forget his and is family's sufferings. So he sang his little rhyme quietly, softly.
Ring around the rosie
The symptoms had appeared on Francine faster than anyone else. Her rosie-red rash had been so prominent, Arthur could have almost pretended it was a bad sunburn, but that was not the case.
A pocket full of posies
Matthew had come home one day very excited, his friend Gilbert had told him about keeping flowers in his pockets. According to Gilbert, if you kept posies in your pocket, they would ward off the evil spirits causing the Black Death, but that was not the case.
Hush, Hush
Alfred's cough had been terrible, especially since it was only him and Arthur in the big empty house. Often the neighbors would complain, forcing Arthur, heartbroken, to tell his son to be quiet. Arthur wished it was just a bad dream, and that he could wake up, but that was not the case.
We all fall down.
All the family he had in the world had fallen, and now it was his turn. Black Death was not selective with who he killed, young or old, rich or poor, they could be the king for all Black Death cared, he killed who he pleased, when he pleased. Arthur knew this, but, in his final minutes, he still prayed that Black Death would spare him, would bring his family back to him, and that they could all live happily together again, but that was not the case.