oh hello! My bad, I guess I never really specified huh?
The ROs are Red, Orange, Green, Purple and Pink!
However there'll be some 'unique' aspects for each romance. Details under cut. Spoiler warning but you knew that lol
For Red:
You must have a good or at least neutral relationship with his son, Ron (yes he is a DILF dad). The two have become attached and heavily rely on each other to regulate/ feel safe after a particular... incident. They are incredibly important to one another.
So if you show any hostility or signs of threat to Ron, his father will obviously not like you. So you must have a decent relationship or you can just eliminate the problem
For Orange:
Orange will have a crush on you, regardless of gender and regardless if you're a parasite or a shapeshifter. Of course you are free to shut them down or use their affection for your own gain.
Just be careful when playing with their heart—you may end up cutting yourself as well
For Green:
Green will like you more if you're a shapeshifter, less if you're a parasite (views you as weaker). They will flirt with nearly everyone, you included. However, they will not take any flirtations seriously and will wave away any sincere admissions.
They'll deny any feelings, so be patient—or prove just how far your devotion goes
For Purple and Pink:
These two are a unique case because they are already in a sorta relationship. To romance one, you must be able to accept the other as well; you do not need to romance or even like both, though you can if you so wish.
They are actually harder to pursue individually; Purple is very territorial/ hostile while Pink tends to miss/ dismiss signs. Additionally, because they already care deeply for one another, they will watch you even closer if you try to romance the other