>>3563907The reason Nanachi is fluffy is because she grew up in a harsh, cold climate. Wanting to be warm was a constant there. The rest were also personal wishes or insecurities held by Nanachi.
The reason Mitty became immortal was because her last sane wish was to not die, so Nanachi wouldn't be hit by the curse.
Also, I have a theory that narahate'd people take the partial form of an abyssal creature. We have seen one that has all the characteristics of Nanachi. The cheek whiskers, ears, fangs, ect.
The change in personality came with age, but mostly the smug/snarky personality came from the cruel things she had to witness, which caused her to put up barriers, a facade. Her shy and cute self comes out whenever she's caught off guard. The change in personality was not the effect of any blessing.