I'll say it was that one punch that made Nagato fall for Ai.. (▰˘◡˘▰)
Actually i think they did a REALLY good job. realistically there isnt some set in stone reason you love someone. The way it led up to his love of ai however went subtly - initially he was enthralled by his beauty and the fact he was super strong, but then he found out hes actually not what he seems and his opinion shifted - instead of him being a emotionless beauty he started to view ai as a wounded strong person and honestly i think thats when he started to fall in love - it was love the moment he realized his value of ai differed from others’ ...he found himself wanting to protect and love ai even to the point of throwing away himself - that my friend is love.
I'll be honest, there wasn't really much of an explanation or events leading up to Nagato falling in love with Ai, but it was a short story so I'll let that pass. Cause dayum this was beautiful and we all need a Nagato to treasure us like this hngg I love the realistic portrayal of the emotions of an assault victim. You don't want no one to touch you, and you practically attach to your savior. The second couple was shit but NagAi have such good communication it makes me cry in *single* T_T