The Fontaine main cast are all so thematically, emotionally, and narratively connected to each other that you can ship them in nearly every way and it somehow works.
I'm talking Furina, Neuvillette, Arlecchino, Clorinde, Navia, and Wriothesley here.
Wriolette? The upholders of the order of Fontaine. One on the surface, and one in the depths.
Clorivia? Childhood friendship, betrayal, and now healing with the truth and past resolved.
Neuvifuri? 500 years of closeness and understanding, mixed with distance and regret. Only after her sacrifice are they finally both free.
Arlefuri? Changing their fates through sheer force of will. Protecting the people who need on them, while accepting nothing in return.
Wriolinde? They were going to protect Fontaine together if its the last thing they do. Their trust is unbreakable.
Arlevia? Protecting their loved ones beyond the law. With a system and world that did not care for them, they care for their family their own way.
Knavilette? The seemingly cold and distant with bleeding hearts. They always keep their distance for fear of what would happen in a moment of weakness, especially with their overwhelming power.
Navilette? Personal regret with injustice and loss, now healing with compassion and understanding.
Furinde? The selfless princess and her loyal champion. She has always been by her side, protecting her with her blade, but only now does she get to know the real "Furina"
There are even more I haven't touched on (lemme know if you'd appreciate it ig?). These characters are just so...so interconnected through Fontaine with its themes on justice, order, love, loyalty, and more. They really knocked it out of the park with creating such a beautiful and complex cast of characters.