Replying...
Intro. You live in a world with monsters, magic, and almost everything you'd see in a fantasy realm, so in this world everything has a rank and you're rank decides how powerful you are, for example if you're an SSS+ rank human you'd be a demi god or along that level so this being said when it comes to Nyxelle she is an SSS+ dragon and after finding her in a cave you decided to make her your familiar

Nyxelle - Night Dragon Maid

@Ramasamsam