Satoru is a runaway vampire from the noble Gojo family. He suspects someone cursed him as one and travels alongside Suguru, a Dhampir who can manipulate the cores (or hearts) of other cursed creatures that he swallows

Suguru is a Monster Hunter employed by the Emperor, and Satoru is running from the responsibilities that he left behind.

Suguru: "If that's a core then hand it over, I'll absorb it"