Help again

So coming on this what if I’m currently doing with wang Lin in btth 😭 I need help with 3 things. 1 how does celestial slaughter work. 2 how does his domain work I get it but it still is hard to understand a little bit. 3 what was the shadow dragon move he used a lot when he was on the planet before he moved star systems.

Ps I kinda wanna read the novel anyone know sites I can read it on I already read the manga for it🫡