As in 'random' demons they somehow got control over, or as a demon lord, ruling over a population of demons?
Can you give details about the MC if possible ? I mean, is he human ? Is he a monster ? Is... et cetera.
AGM; one of his astral souls is a demon sovereign constellation that allows him to summon and control demonic beasts.
I have not read the novel yet ,only read the description but i do remember that it was a CN and the word Oni was used