Operation Babel: New Tokyo Legacy

I unlocked this by going to the Medical Lab then "Medical Consultation". I then selected Persona and selected a character. If you choose to fight friendly variants, it will make your characters more evil while if you choose to observe and let friendly variants leave, it will make your characters towards the good side (thank to Rozalia1 for confirming this). For best results, use a neutral character for this trophy, since as long as you've either been observing friendly variants or fighting them, their personality alignment will move in either direction.