Country of Ember or Death and his friends

There is a scourge threatening the lives of millions of Nigerians.
No, not terrorism, or AIDS or cancer. Although those are terrible things too. It is the evil face of the -ember months.
As the months count off to the end of the year, in what is known as the curse of the -ember months, there is a deluge of people dying in deceptively normal ways.
Death, it appears, suddenly realises he has a 31st of December deadline and an unmet target of souls to harvest so he has to ramp up his activities.

It is unclear why the threat of the -ember months is so prevalent here. Either Death and his minions have to concentrate on one location in what little time they have and it is always Nigeria they choose. Or Death is more organised in the Western world and he kills regularly throughout the year to meet his targets rather than focus all his effort at the end like he does here.

Whatever the reason is, the end of the year sees the country turn into a killing field. People huddle in churches praying against the spirit of the -ember months. They make t-shirts and stickers. Like this one that says: “Mber Months: Back to Sender!”
Huh? Back to which sender? Pope Gregory of the Gregorian calendar? Does he know you don’t want his months?
I don’t think you can return months like they are unused data on your phone plan.

Meanwhile Death never thinks to switch things up. He never goes: “Maybe I work a little harder in May and June so I don’t have to struggle at the end.”
Death is chillaxing mid-year. No one in the country died in July and that didn’t raise any eyebrows. He is lying on the couch, his black cloak bunched up around him, watching Scandal. He is eating a hunk of watermelon, spitting the seeds into a saucer. He is doing stretches from this yoga DVD he bought on Jumia. His stress is melting away. “Eh, I’ll just pull some all-nighters in November and December. It will be fine.”

Then the end of the year comes and his friends call him:
“Hello. Yo Death, meet us at the lounge, we hanging out.”
“Sorry, I can’t come. I’m swamped with work, you know how the -ember months are.”
“For real? Where you at?”
“Ugh. Nigeria.”