In Revolt of the Beastmasters, the Ancestors send Tarnum to free the Mudlanders from Erathian control. Even after hundreds of years of slavery, the Mudlanders are determined to overthrow their masters. Tarnum appoints the Gnoll, Brellick, as a captain and the Witch, Adamina, as his advisor. He also trains Droglo, a human boy who was raised by Mudlanders. The Mudlanders defeat opposition from Lord Onsten and Baron Paglon before Mad King Gryphonheart of Erathia takes the rebellion seriously.
Mad King Gryphonheart sends his son Niven to put down the rebellion in Earl Rambert's territory, though he secretly thinks his son will fail. Tarnum captures Prince Niven and shows him what slavery has done to the Mudlanders. Niven eventually sides with Tarnum, and he is released from his prison. The Mudlanders force Rambert to retreat to another castle and leave many of his prisoners behind. When Rambert threatens to kill the remaining prisoners, including Adamina, if Tarnum does not return Niven, Tarnum sends Brellick, Droglo, and Niven to make the exchange after harming Niven so that he looks like a true prisoner. However, Rambert ambushes their army and kills Brellick. Droglo then kills Rambert, and the Mudlanders soon win the battle. To prepare for the final battles against Mad King Gryphonheart, Tarnum sends Droglo to request the aid of the Barbarians of Krewlod (the Wastelands).
Adamina and the other wisewomen name the new Mudlander nation "Tatalia," a word which means "community" in the forgotten Mudlander language now only known to witches. In Erathia, the nobles displeased with Mad King Gryphonheart name Niven as their new king. King Niven mounts an army to join the army of Tatalia in the fight against the old king's remaining supporters. Droglo finally discovers Tarnum's identity as the Immortal Hero, but accepts that he has changed. Tarnum and Mad King Gryphonheart meet in battle and deal each other seemingly mortal blows. However, Tarnum is immortal, and he slips away before his body can be buried. Droglo becomes the new leader of Tatalia.
