>>52815618He has an apple because he's a teacher.
It's in contrast to all the other typical "dragons" on his team because he came from a clan/family of dragon trainers, but the Flapple represents the part of him that wants to teach; he doesn't see it as something that has to exist in contrast or opposition to his origin as a dragon trainer, but just another part of his identity that can coexist within him (also apples/fruit are one the most common practice subject for still-life paintings, so it also fits with him being an art teacher).
