Take My Crown, I Only Want Him (Atsuhina)
22 parts Complete The Civil War in Japan lasted a long 15 years, until each kingdom of Karasuno, Inarizaki, Nekoma, Fukurodani, and Aoba Johsai's supplies and soldiers were depleted. They finally came together to form an alliance between each kingdom to rise up together out of the depression that the war left behind.
Now two years later, each kingdom decided to gather all of their heirs in the kingdom of Karasuno to allow them to form strong ties that will last when each heir inherits the throne. Prince Shouyou has heard every last detail of the princes, excitedly awaiting their arrival, but the one he's been warned about the most is the infamous Prince Atsumu. However, once Shouyou meets him, he doesn't understand why everyone despises him. He's just being honest, which is so refreshing for Shouyou that he just can't stop spending time with him.
Prince Atsumu has met every last fake, self-serving, arrogant prince under the sun. The last thing he wanted to do was attend a gathering with four of those kind of princes. Unexpectantly, once he meets Prince Shouyou, his opinions begin to change. He actually starts to want to talk to someone other than his twin.
---Art is not mine credit to the artist on tumblr (I can't find their account anymore sorry)