I had a funny idea as I was playing, and I wanted to share it, so I'm leaving it here as a joke/suggestion.
Akarion as the sole individual to be spared during your insane haremification rampage. He has not been altered, but he hasn't been able to affect anything either. Instead, your poor half brother has been a horrified spectator as his brother-from-nowhere suddenly upends everything.
And then, if you've also been untransformed by the end, as the new world order rises, the two of you become unlikely friends and siblings. Though begrudging on his part, you two are the sole survivors of the old world, and bond over that connection.
Akarion: I guess I'm grateful that you had mercy on me, but... why all of this? You complete nutcase.
Lewis: The voices in my mind. I heard, "All the others. Harem". But when it was your turn, I realized the voices actually said, "Spare 'em".
Akarion: You're fucked in the head.
Lewis: The head? If you mean the lower one, yes, frequently.