Niven Gryphonheart is the son of Mad King Gryphonheart, ruler of Erathia. When his father dishonors the nation by brutally persecuting a group of Mudlander slaves trying to escape and create a new homeland for themselves, the nobles of Erathia name Niven the new king. He appears in Revolt of the Beastmasters, the seventh part of Heroes Chronicles, but only appears in-game in The First Tatalian War, the eighth and last scenario.