Clan Ritz is a clan headed by Ritz Malheur, one of Marche Radiuju's friends from the real world in Final Fantasy Tactics Advance. Second in command is the viera Shara, who befriended Ritz after her arrival to Ivalice. Although it appears to be an all-viera group (with the somewhat exception of Ritz, who is said to have the "blessing of the forest"), it is unknown how many members work for Clan Ritz, nor are their base(s) of operation, if any, revealed. Clan Ritz aides Clan Nutsy with various missions as NPCs.
Marche encounters Clan Ritz in mission #003: "The Cheetahs", where Clan Ritz has also responded to the request to bring in the band of men known as the "Cheetahs". After dealing with the hostile group, Marche and Ritz enjoy a short reunion, where Marche asks Ritz to help him find a way back to the real world. Marche is shocked as she doesn't want to return to a world where she has to dye her hair to fit in. The clans meet again in mission #048: "S.O.S.", due to Clan Ritz sending up an emergency flare in a call for help, and yet again in in mission #107: "Old Friends", where Clan Ritz claims they've bitten off more than they can chew.
The two clans meet one last time in mission #023: "Over The Hill", when Clan Ritz comes in force to stop Clan Nutsy from reverting the world. After defeating Clan Ritz, Ritz allows Marche and the rest of Clan Nutsy continue on their quest with the promise that she won't interfere with them again. Shara asks Ritz why she allowed them to leave, and Ritz answers "every game must end".
Although the rest of Clan Ritz isn't seen after the events of "Over The Hill", it becomes possible to recruit both Ritz and Shara through the missions "Mortal Snow" and "A Maiden's Cry", respectively.