Different scenes of main characters fighting and beating each other up. Violence is not meant to be implicated in these types of scenes
A villain orders another villain to be executed motions this by dragging his thumb across his throat.
After falling into a volcano, a man gets his face burned by a sudden burst of lava. His scar can be seen as graphic.
This show is definitely darker than its predecessor. Characters die both on and off scene in violent manners (one is frozen alive and another drowns), dragons are imprisoned and often killed (although the latter is never seen), and there are many action sequences that can be graphic to some.
Human bones are seen lying on the ground in one episode, including a couple of skulls. Heavily implying they might have been eaten by a large dragon and its pack.
A captured enemy runs into some bushes and is later heard screaming afterward. The screaming stops a couple of moments later and dragons appear, implying they killed and/or ate the man.
One of the series' primary villains has a visible scar on the side of his neck that appeared to be caused by a dragon.
A villain has a large burn scar that covers nearly half of his face, he also has a blind eye.
In a few episodes, dragons are heavily scarred and a couple of them are close to death, but they all survive. Dried blood and open wounds are usually seen on them, one dragon suffers from a severe burn on its back.