Yu-Gi-Oh! GX Terminology

Spirit Gates
The seven Spirit Gates are gates hidden deep below the Duel Academy, used to protect the Sacred Beasts. They can only be opened by obtaining the seven Spirit Keys, which can only be won in a duel. Nearing the end of the first year of Duel Academy, the gates are opened, and Kagemaru announces that the gates can be opened by posessing enough dueling spirit.

Misgarth
The Misgarth Kingdom was the royal family of Prince Ojin. They were responsible for sending the brainwashing satellite, that Sartorius intended to use to make the world into members of the Society of Light, into space.

Genex tournament
The Genex tournament, or GX tournament, was an event created by Chancellor Sheppard during Jaden's 2nd year at Duel Academy. It showed duelists such as Prince Ojin (a prince whom lost his country's Satellite Cannon to Sartorius after being subjected to the dreaded First Turn Kill), a reappearance by Blair (a young duelist appearing at Duel Academy with the hope of winning the tournament and getting into Slifer Red), Lucien Grimley (a duelist from North Academy who sold his soul to The Grim Reaper in exchange for drawing power), Frantz (an ex-card designer/duelist whom lost his job to Chumley and afterwards appeared at Duel Academy with a copy of The Winged Dragon of Ra, only to get beaten by Jaden thanks to Skyscraper 2 - Hero City, a card which Chumley had designed for him), and many others. Chazz was eventually declared the champion of the Genex tournament after defeating Blair Flannigan.