Mosa Rex is a fictional character from Kishiryu Sentai Ryusoulger, a giant Kishiryu dinosaur-like ally associated with the Ryusoulgers. He is a powerful support and combat partner who helps the team in battles against the Druidon Tribe. Mosa Rex is known for his strong presence, aquatic-themed design, and heroic role as one of the ancient Kishiryu. He serves as both a formidable fighter and a symbol of the bond between the Ryusoulgers and their dinosaur companions.