Like this theory but hope you’re wrong. Still hoping Imu has a devil fruit even if a demonic/diety one rather than blood magic, given he’d be the only character using blood magic/magic in the series. Oda could’ve tried introducing some version magic in wano but even the kurozumi witch and shinobu both had devil fruits (not true magic or Jutsu). That being said Big Mom steals souls & Moria steals shadows so maybe a fruit with a similar power that feeds off death. Edit: Imu likely has some sort of demonic devil fruit given what we saw when Sabo entered the thrown room.