[@Dezuel]
>Does this mean that the Leviathan have several heads?

No.

>And how would one go about possibly defeating something which can regenerate their head?

He doesn't have infinite mana. It takes a lot to do it. With his current strength, he can only do it once before having to hibernate. And a dragon's core is its heart, buried deep beneath its scales, bones, and meat.

>Oh and also for the transformation itself how big the Leviathan actually is and if it has more limbs, heads than the common dragon.

It looks just like your ordinary dragon, only all of its body are covered in spiky dark red scales. Its size is around 10 meters tall and 20 meters wide.