The Nephew and Uncle Who Died on the Same Day

Looking at the dynasties that have existed throughout history, while half-brothers have been killed, cases of full brothers killing each other are truly rare.
In Korea, which has possessed particularly strong morality since the era of Dangun, the only exception is when Grand Prince Suyang (King Sejo of Joseon) killed his full brothers, Grand Prince Anpyeong and Grand Prince Geumseong.
The names Suyang and Geumseong share the same reason.
While the Hanja characters are written differently, the pronunciation is the same.
It is said that Geumseong particularly followed Suyang and had a similar temperament.
It is said that he was not only good at studying but also as skilled in archery and horsemanship as Suyang.
Therefore, rather than his eldest brother Anpyeong, he was closer to his second brother Suyang, with whom he used to go hunting, and Suyang also cherished his younger brother Geumseong dearly.
When King Sejong finally saw his long-awaited grandson, King Danjong, he entrusted his childhood upbringing to the household of Grand Prince Geumseong.
At least he was a relatively young uncle, with only a 16-year age difference...
Needless to say, what was the relationship between the two who lived together like that?
The reason Grand Prince Geumseong tried his absolute best to protect his nephew until the end was also because of the instruction from his father, King Sejong, to teach and protect him.
On November 16, 1457, the nephew and uncle
were killed on the same day by another uncle and brother.
It is said that as Grand Prince Geumseong received the poison, he bowed not toward the capital of Hanyang, but toward Yeongwol, and shouted:
"My King is in the North."
It was from this moment that Joseon could never become powerful and prosperous again.
Sejo, Grand Prince Suyang, Yi Yu, is not a human being.
If there is an afterlife, how will he face his father, King Sejong, and his brother, King Munjong?