Dragon upadtes

Why did Toothless become the king of ALL dragons, not just the alpha of Berk's dragons? Why did the dragons in the Hidden World immediately accept him as the king in there too? I always imagined there would be multiple nests and alphas in the dragon world, so why Toothless exactly got the title of "king"?Brahh, id just like to say i really adore your artstyle and talent and have major respect for you---Damn, I really love your artstyle, it's so cool!I'mma have to request or art trade you A\

Dragon yu. Yum yum. Mmh. Yesh. Hm yesh mhn yeshh