Kareth wields the Starslayer (A sword) that can phase through solid, non-living objects.
Kareth made the deciding choice to destroy their home planet Ajespa with his Starslayer, cutting the population of the Avidrenes by 75%. He was then marked a traitor my the Jespan High Party. He banished and imprisoned every single member of the Jespan High Party and Underlords so that he was the Jespan’s only ruler. He believed that the party was corrupt. He was rendered unable to fight after Elias destroyed his sword with an energy manifested sword.
Kareth or King Malvorr is an egotistical dreamer who feels the need to overthrow corrupt or morally wrong groups, shown in his traitorous behaviour. Kareth is authoritarian, prejudiced against humans, and deeply frustrated by his civilization's decline. He carries tremendous anger toward his late wife Helena, believing she betrayed him regarding Rae's mission on Earth. His leadership style is intimidating and violent, willing to order the torture and execution of enemies without hesitation. Kareth does learn that humans shouldn’t be underestimated and that this sacred power of teamwork is unbreakable, making him realise that his daughter has indeed grown into a strong woman.