It's very difficult to pick a favorite character. Since it's similar to asking who is your favorite child.
Damien is a very loveable and I enjoying the dynamics of his route depending on how you treat him. His route lock brings up a very interesting premise for what is to come.
Kate, is just a pure cinnamon roll, that makes corrupting her all the better. Her romance route has the potential to be both some of the happiest and most depressing moments in the whole game.
Violet is certainly a fan favorite has the appeal of putting a rich haughty girl in her place or feeding into her lust. A relationship that rises above it's base desires and into something more. Really looking forward to showing what he have planned further for her.
Matt loves to be in charge and have power over people, but through his despicable attitude and lack of care makes some great scenes in how you can deal with him and in many cases elevates other characters in how they can defend you from him.
But we can't forget about Nathan, he's a new addition and we've worked hard on him. He's a great, observant, and cares a lot about others, but he knows when not to get involved with people who aren't serious about their commitments.
There's more I'd like to talk about, but I will say that what's to come for him will be a treat.
Hope that answers your question. ^^