I read this in novelcool spoilers ahead . . . . . . . . . . . . . . . . . . . . . . . . . ...

I read this in novelcool spoilers ahead
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

Two members from each of the twins’ groups are kidnapped by a rival faction. Both twins set out separately to rescue their people. However, when they cross paths, they immediately forget why they were there and start insulting each other instead.
Meanwhile, one of the kidnappers becomes obsessed with the black-haired twin’s sword technique. Wanting to avenge his cousin—who is actually still alive but lost an arm—he challenges the black-haired twin to a duel to death. The black-haired twin accepts.
The white-haired twin becomes jealous. He hates seeing his brother take a fight with some random guy so seriously, because in his mind that level of seriousness should be reserved only for their battles with each other.
The guy who is supposed to decide which twin will become the heir watches the whole situation unfold and jokingly comments that the scene reminds him of netorare—like watching a partner cheat.
After the black-haired twin subdues the challenger, the two of them begin talking. The white-haired twin immediately interrupts and pulls his brother away, clearly jealous.
Then the twins go up to the roof of the building to have what they believe will be their final battle to the death. But just before the fight begins, the black-haired twin admits that he cannot do it. He says he wouldn’t be able to live in a world without his brother—and throws himself into the void.
The white-haired twin, realizing he feels the same way, jumps after him.
Both of them survive the fall.
After that, they decide to merge their groups instead of fighting each other—and they kiss again.