i just finished the demo and did all the route - spoilers alert for those who haven't played all routes yet.
at first i thought my favorite will be septem, i just like the whole controlling type of character but afte playing all the route. my favorite is unum, he is the sweetest out of the three love interest right now and has the wholesome (? compared to the two) storyline. the whole parenting and whole getting to know each other made me fell inlove with unum and i look forward to him the most. (hope he gets more yandere if he is one but if the tag is not for him, its also fine.)
nulla, on the other hand, intrigues me. i didn't expect for his storyline to be that gruesome but i am not complaining as someone who enjoys sick, dark themes in fiction. in terms of the lore in the game, i feel like his route is the most important and i am looking forward to how his route goes from the act 2. (yandere tendencies i crave)
septem's route for me, was unfortunately boring? but i feel like the game was specifically going for that with septem. a constant, seemingly unending routine as your body/puppet rots. nonetheless, i look forward to his story route as well. (yandere tendencies i crave pt.2)
overall, the concept of the game is interesting. the story and its characters are well-constructed. i can't wait for how the game will execute the story.