Mami's interactions with Fou-Lu in general — particularly explaining to Fou-Lu she didn't quite understand his rant about how "It's in Your Nature to Destroy Yourselves" but she couldn't stand to see him sad. And a Tear Jerker moment when she declares all she had ever hoped for was that they could live a normal life together. Made even more of a Tear Jerker, of note, because afterwards Mami ends up being captured as Human Resources for the Carronade.
After it's revealed that Ershin is just a suit of armor brought to life by Deis' Endless aura, Ershin asks Nina what to do and on several occasions during the game, Ershin seems to depend on Nina a little and Nina happily tries to help, it's quite adorable and pays off since Ershin takes the advice to heart.
Nina's considering Ershin to be one of the party even if it's a suit of armor who is alive because of Deis' Endless aura.
Ershin trying to comfort Nina after Elina is given a Mercy Kill, best of all, it's Ershin doing it, not Deis.
Ursula and Scias comfort Cray after what happened and both agree he did the right thing.
The final battle, in which most of the party is convincing Ryu (in the Good End) that Humans Are Special.
It's considered bad luck from the sailors of Chikk to have women onboard their vessel, so to prove they can handle life on the sea, Nina and Ursula volunteer to spend a night in the brig. After fighting a few ghosts, Nina remarks that she might have been scared, but she was really glad she faced her fears, and more importantly, she was glad she faced them with Ursula. Then thelice come out.
Manga Adaptation:
Mami's interactions with Fou-Lu in general — particularly explaining to Fou-Lu she didn't quite understand his rant about how "It's in Your Nature to Destroy Yourselves" but she couldn't stand to see him sad. And a Tear Jerker moment when she declares all she had ever hoped for was that they could live a normal life together.
And as per usual, yes, the manga cranks it up to eleven in a very explicit Ship Tease to the entire FouMami Ship community including an adorable scene featuring Mami and the old village fisherman teaching Fou-Lu how to fish...
