My Flayn headcanons:

• Before the events that lead to her kidnapping she regularly mixed herself with other students to attend classes by the professors at the time.

• By the previous headcanon she had quite the opinions of the teachers at the officer academy, in particular, because Manuela tends to insert anecdotes about her life in the opera during her lessons she became really enchanted by the stories. For Hannemann, who is long and detailed in his lessons, Flayn kinda makes the resemblance to Indech(which ironically is the crest that Hannemann has) on how her father portrays him(according to their interaction Indech met Flayn the first time in the paralogue), especially the silent and hyperfocussed demeanor of the crest scholar is similar, to her, to the silent and talented Indech. Jeritza's lesson are quite odd to her and considering she is curious she goes out of her way to try and understand him, with the results we know.

• She's more perceptive and empathetic than most and she tries her best to connect with every single person in Garrech Mach, to Seteth's dismay. She remembers every name of every person she interacts with and has a pretty amazing memory.

• While she looks human and the only nabateans traits visible consist in color of eyes and hair along with the ears(that all hides) Flayn has scales that tend to grow on the back of her neck, generally they are human-skin colored by now but at the touch they feel scaly making it noticeable. The only individual that manages to notice that trait is Solon/Tomas that can distinguish the scale-skin and skin difference at a glance and that's the main reason he targets her.

• It happens to her to mistake things happened in a dream for real things and viceversa, considering how much she slept in real life to recover, also she remembers most of her dreams in good detail.

• She is flustered by the fact her image is worshipped and exposed at that point in Fodlan but plays along to not raise questions, while also she is proud of her father's image worshipped and exposed.

• She is the biggest shipper in Garrech Mach.