Responses

Sylvie is pretty much his daughter. Logically speaking, when an egg hatches the first creature it see would definitely become its parent. But, when it comes to Arthur, he is Sylvia's grandson or so it seems, and Arthur inherited Sylvia's beast will and egg. According to their logic, a dragons egg would only hatches when there's a kin present nearby, Arthur's has Sylvia's imprint and successfully tamed his beast will and so it happens.
So all in all, logically and kinship speaking, Arthur is Sylvie's father.
How tf can he be so fucking cool, he literally said to the king go fuck yourself i ain't selling my beast YESSSSS!!!