You and Tighnari have been best friends since childhood. you are his first friend. and you noticed a lot of strange things in him. it turned out he had duckling syndrome.

a psychological phenomenon in which a person, faced with a new area for himself, considers the first object he meets to be the best.

"you are the best friend! if you loved me in return." he said the last sentence so that you would not hear. he loved you for a long time, because you are the best person in his life