Emperor Caligula
Wikipedia
A Guide to the Trials of Apollo series by Rick Riordan
Emperor Caligula is the main antagonist of The Burning Maze and one of the three main antagonists in The Tyrant's Tomb alongside Commodus and Tarquin. He was born into the first ruling family of the Roman Empire, conventionally known as the Julio-Claudian dynasty. Caligula was ambushed by his Germani guards which led to his mortal death.
Following this incident, he employed the Strix and the Pandai to work for him while his fellow emperors continue to use Germani. Many years later, Apollo and Piper were brought to Caligula by his talking horse Incitatus as Caligula has the Pandai they subdued executed. Before he can have Meg and Jason Grace executed, Caligula is stunned when Apollo threatens to hurt himself. After Apollo stabs himself, Caligula kills Flange following the news of the attack on Camp Jupiter ending in failure. Caligula then sails north with his guards. Medea meets with Caligula and advises that he performs a ritual before Apollo dies. Caligula later fights Jason and Tempest on the back of Incitatus where he manages to kill Jason. After making sure that he is dead, Caligula sets sail for the Bay Area. Later, Caligula joins forces with Commodus and Tarquin to destroy Camp Jupiter but ends up being killed by Frank.
Following this incident, he employed the Strix and the Pandai to work for him while his fellow emperors continue to use Germani. Many years later, Apollo and Piper were brought to Caligula by his talking horse Incitatus as Caligula has the Pandai they subdued executed. Before he can have Meg and Jason Grace executed, Caligula is stunned when Apollo threatens to hurt himself. After Apollo stabs himself, Caligula kills Flange following the news of the attack on Camp Jupiter ending in failure. Caligula then sails north with his guards. Medea meets with Caligula and advises that he performs a ritual before Apollo dies. Caligula later fights Jason and Tempest on the back of Incitatus where he manages to kill Jason. After making sure that he is dead, Caligula sets sail for the Bay Area. Later, Caligula joins forces with Commodus and Tarquin to destroy Camp Jupiter but ends up being killed by Frank.