It's incest, but surprisingly, it's fluffy and wholesome incest with realistic dynamics and complexities in their relationship... rather than the deranged co-dependency twisted love stemming from abusive childhood trauma, it's more like extreme brocon love that shifted into romantic love. honestly, there is no reason for it to be incest. this didnt have to be bl. and it still would've been a good entertaining story. but man the art is adorable.