Dirty Bit
That's him, officer
@Dirty Bit
Dare I ask?
Turns out the war that the series had opened with was brought upon by two individuals who used to be one being. Said being pined for a princess’s affection, but he split himself apart and had the human part get with her, leaving the other to languish until they went on to become an eldritch beast via a dangerous method. The two cannot kill each other, because they would both die, but their love for the princess - who ended up spending her time in Centaurworld upon her intervention after catching wind of their actions - still remained.
Funny enough, she finished the job herself in the end after the strife had reached a fever pitch.