Cleru is the Male protagonist of Summon Night: Swordcraft Story. He is a young Craftknight, who wants to follow the footsteps of his father, the Craftlord of Iron, Shintetsu.
Cleru is the son of the last Craftlord of Iron, Shintetsu, who gave his life to save Wystern three years before the events of the game. He is a Craftknight in training from the Silver Guild and has hopes of one day being her father's successor as the Craftlord of Iron.
At the beginning of the game, Cleru enters a tournament for young craftknights that will decide who will become the next Craftlord of Iron. As Cleru wins his way up the ranks of this tournament, he becomes close friends with three of his fellow craftknights: Sanary, Varil, and Razzy. He learns the dreams that these people wish to make reality by becoming craftlords during the tournament as well. During the tournament, he discovers a plot made up by two of the craftlords, Lubert and Ureksa, to help an enemy nation, Deigleya, destroy Wystern to gain fame and fortune in the process. He also manages to rescue Tyram, a craftlord who had been kidnapped by them and after a number of battles, he manages to ruin their plot with the help of Varil and one of the Craftlords, Sakuro. Back in the tournament, one of his friends, Sanary, makes a pact with an evil summon creature of fire named Parista. Once Cleru defeats Sanary in the tournament, Parista possesses Sanary and brings her deep into The Labyrinth, as Parista wants to kill Cleru to get revenge against Shintetsu, but Cleru manages to defeat Parista with the help of a summon creature named Kuhyra, and saves Sanary. After this, Parista and Kuhyra return to their homeworld, Sapureth, and Cleru goes on to win the tournament, as well as the title of Craftlord of Iron. Once he becomes the Craftlord of Iron, he decides to make his friends' dreams come true as well as his own.
Alternately, if the player chooses to play as Pratty, Cleru will not appear at all.
Cleru, as a Craftknight, is able to wield all possible Weapons, from the all-rounded Swords, the heavy Axes, to Drills. As a player Character, his stats can be altered to fit the player's playstyle.