Muichiro grew up being a slave so he never expected anyone to befriend him. When his fourth master's nephew, Tanjiro, visits their village after a long time, he didn't leave him alone and always sticks beside him. Muichiro asked Tanjiro why he wanted to be his friend when he is just a lowly slave, and with all his sincerity... Tanjiro replied, "it's because I want to see you smile."

𝚃𝚊𝚗𝚓𝚒𝚛𝚘 𝚇 𝙼𝚞𝚒𝚌𝚑𝚒𝚛𝚘 𝙵𝚊𝚗𝚏𝚒𝚌 Tanjiro always seemed to be intrigued by the mist pillar, Tokito Muichiro. His blank, crystal blue eyes were fascinating and full of secrets. He wanted to know more about the pillar and who he was. He wondered what he would find out in his effort to know the younger boy.

The mist and fire kingdom had problems so they use their sons to marry each other to marry to solve the kingdom's problem what will happen next?