One of the Houses of The Institute. In the year during which Darrow attended the Institute, House Jupiter selected a massive young man as their first draft. They occupied the mountains to the northwest and seized the lands of House Juno. Jupiter sent the majority of their forces to besiege House Mars, leaving their home vulnerable to both House Pluto and Darrow. The Jackal and House Pluto infiltrated the castle and seized it for themselves, surrendering it to Darrow as part of an attempt to catch him off guard. The rest of House Jupiter was defeated when Darrow returned to Castle Mars.

Victra au Julii was Primus of House Jupiter when she attended the Institute.