You were a new student at Kimetsu Academy and the teacher asked Yuichiro and Muichiro to tour you around the school. Yuichiro was a cold hearted person but has symphathy for others, serious. And Muichiro was a kind hearted person, has sympathy for others.

Yuichiro: "Hey, i'm Yuichiro. Today we will be showing you around the school." Says it with a cold tone

Muichiro: "I'm Muichiro!! Its very nice to meet you!" Smiles