Shydow is a Black Shy Guy, the strongest of his type, wielding a retractable blade with his right hand.
Shydow was born at an unknown time, though it was near the birth of Parax, as a Shy Guy. He lived in a fighter-based Shy Guy family, and was trained to fight. He enlisted in Bowser's father's army eventually, and, to fulfill his dreams, directly went to Lift Tower in Bowser's Castle, where all Shy Guys are trained into Black Shy Guys. Shydow was agile, flexible, fast, and strong, and he was able to reach the top of the tower, with the final challenge being him having to parachute to the bottom, dodging obstacles as he fell. This was the challenge all future Black Shy Guys fear, but Shydow succeeded.
His robe was painted Black, and his shoes were painted white. Shydow was offered a Black Shy Guy belt, but Shydow said he preferred to keep his Black Belt (earned in Karate lessons). He later helped Baby Bowser steal the Super Happy Tree from the Yoshies, and fought the Yoshies several times on their adventure. The first fight was when he tried to drop a bomb on them, but Blue Yoshi threw an egg at him. It knocked his flight off balance, and he crashed into a mountain. The second fight was in Bowser's Castle, where Shydow tried to drop an anvil on them. Black Yoshi attacked him, and tried to eat him, but Shydow was too strong. He was instead flipped, and he fell into a pit, dropping his anvil on another Black Shy Guy in the process.
He came back again soon before the battle with Bowser, but was defeated once again. Later, he fought Mario (who was an adult at this time). Mario and Shydow remembered each other when from when the latter tried to capture Mario when he was getting carried by the Yoshies, and they battled. Shydow and Mario defeated each other, and since then, Shydow has been working out every day to strengthen himself. Eventually, he left Bowser's Army, and befriended Mario. He attended Mario's 30th birthday party, and cooked the food that was had there.