Tsugumi Ohba, the writer of "Death Note", explained in the postmortem follow-up volume that the meaning behind "MU after death" was that "the dead person should never come back to life, and it's cheating to revive dead characters as manga. So it became MU". Ohba further explained that "all humans die someday, and when we die, we can never come back to life, so let's do our best while we are at it" was the single most important theme Ohba wanted to express in writing the series.