So, technically, Bushido doesn't have them. However, they do have the Kairai for the Cult of Yurei. They're pretty close. No, they won't eat your brains. But they will gladly bash you to death with a giant mallet or stab you with farm implements at the behest of their masters. So there's that.
These new sets let you expand your options for Kairai models on the field. The set gives you pieces to create the "B" Kairai Villager, Kusatta Kairai Kairai Farmer, or Kairai Militia. So now you can give your not-quite-zombies a bit of a different look quickly and easily.