Shin Mouri is one of the five main warriors in his series, known as the bearer of the Suiko armor, which represents the element of water. He is the oldest of the group, being fifteen years old at the start of the television series, with his age progressing to eighteen in later storylines. His birth date is March 14, 1973, and he was born and raised in Yamaguchi Prefecture, specifically in the coastal city of Hagi.

Shin comes from a family with a long and distinguished history. The Mouri clan is descended from the famous naval general Mouri Motonari, and for generations, the family’s duty has been to protect the Hagi Sea. His father, the former leader of the family, died when Shin was young, leaving him to be raised by his mother, who has a weak heart and manages the family’s pottery business, and his older sister, Sayoko, who is ten years his senior. Because his sister eventually plans to marry and the family business would traditionally fall to him, Shin has been trained since childhood in martial arts like the spear and bo staff, as well as cultural practices such as the tea ceremony, flower arrangement, and cooking. He also enjoys basketball and swimming.

The Suiko armor is intrinsically linked to Shin’s heritage and his connection to the sea. As part of a rite of passage for the men of the Mouri family, he dove to the bottom of the deep Hagi Sea without an air tank. There, with the help of a childhood orca friend named Suiki, he discovered the armor’s crystal in a crevice. When he later told his mother, she revealed she already knew of the armor’s existence, saying, “At last it has come”. The Suiko armor draws power from any water source, and its design allows Shin to breathe underwater indefinitely, withstand immense pressure, and even has a face guard that functions as goggles for underwater vision.

In battle, Shin wields the Suiko Yari, a unique weapon that combines the functions of a trident and a mancatcher. He also carries a tanto dagger on his back and claws on his forearm gauntlet. His signature special attack is the Cho Ryu Ha (Super Wave Smash), which unleashes a devastating, horizontal pillar of pressurized water. This attack is powerful even on land but becomes exceptionally more potent when used in or near water.

Personality-wise, Shin is characterized by his gentle, polite, and considerate nature. Having been raised primarily by the women in his family, he is soft-spoken and dislikes unnecessary fighting. He often acts as a stabilizing and caring presence among his fellow warriors, and his thoughtfulness extends to being an excellent cook. However, beneath this calm exterior lies a fierce and formidable fighter. When truly angered by a merciless enemy, his rage is described as quiet, focused, and long-lasting, making him potentially the most dangerous of the five warriors when provoked. Despite his maturity, he is still a teenager who can show moments of youthful naivete and mischief.

Throughout the story, Shin’s role is not only as a powerful fighter but also as a loyal and sincere friend. He embodies the virtue of “Shin,” which means faith or trust. His close bond with his orca companion, Suiki, and his ability to communicate with sea life demonstrate his deep empathy. A significant moment in his personal development involves his family, when his sister’s engagement threatened to force him to abandon his duties as a Trooper. By confronting his future brother-in-law and reaffirming his bond with his heritage and the sea, Shin resolves this conflict, allowing him to continue fighting alongside his comrades. In later story arcs, he continues to struggle with the burdens of being a warrior, at one point questioning his destiny and even refusing to participate in summoning a corrupted armor, showcasing his strong personal convictions and reluctance to engage in battles he deems unjust.