Following his meeting with Tanjiro Kamado and the return of his childhood memories, Muichiro's once empty looking eyes seem to now have a hopeful glimmer that is accompanied with a more upbeat and cheery expression, reminiscent of his former demeanor before the death of Yuichiro. However, before the death of his twin brother when the siblings were eleven, Muichiro's personality was that of a much more compassionate and optimistic individual, the polar opposite of his current disposition.