Alternate: Dark Joujima Yuuki
Previous Zodiarts: None
Motif: The Joker from the trump card
Abilities: Can control explosive energy in the form of cards.
Supernova: Can create a mass of explosive energy in the shape of herself.
First appearance: Kamen Rider Fourze 43
Voiced by: Konno Hiromi
Body double for Yuuki: ??
In the myth, the twins Castor and Pollux were raised by a centaur named Chiron, who later became the constellation Sagittarius. Gamou displays a kinship with dark Yuuki.
Only one of the brothers was immortal. After stealing the wives of their cousins Lynkeus and Idas, their relationship with their cousins is strained.
The four of them decide to go on a raid. Idas proposed splitting the cattle among just two instead of four. He splits a cow into four and have an eating contest to see who gets the spoils. Idas equickly eats his and his brother's portions. The twins realize they had been tricked and reluctantly let their cousins take the cattle, vowing revenge someday. Gemini Zodiarts has a line about splitting things into four when she runs out of cards for the Riders.
Eventually they fight their cousins and Castor is killed. Pollux asks Zeus to put them in the sky so that they can be together. In the show, one of the Yuuki's will eventually disappear.
The cousins that they fight with are named Lynkeus and Idas, which happen to also be the name of Gemini Zodiarts' cards. Lynkeus is the red card that blows up instantly. The controlled explosion is named Idas.
If the kanji for Joujima is interpreted as Jousima, then Jousima Yuuki is an anagram of "I am Soujikyuu". Soujikyuu 双児宮 is the Japanese name for Gemini's symbol.
Wiki article on Gemini astrology
Personality: Positive: outwardly expressive, extrovert.
Despite being compatible with other air signs (Libra and Aquarius) Yuuki does not seem to get along with Hayami and had a rough start with Eline. Gemini does get along with the fire sign Sagittarius Gamou.