Kotetsu first appeared in BW95. He appeared alongside his main parthner Riolu and was meant to compete in World Tournament Junior Cup, but much to his dissapointment , he was too late and the Cup was over already, so he left off. Later in the same episode he shows upafter Ash and his friends say their ferewell's to Dawn, there he officialy announced that he is going to enter the Unova League, he originally mistakenly thought that trainers only needed seven badges to enter the League but found that he eigth badges to enter. Jervis tells him there is a gym near Town located in Humilau City. He decides to head there, Ash and friends offer to go with him and gladly accepts.
Kotetsu has a habit of making a lot of errors like he thought trainers only needed seven badges to enter the Unova League, and thought that it was going to take in Ecruteak City in the Johto region.
kotetsu's ferrothorn is the second pokemon in Kotetsu's team. It first appered in BW096 where it went up agaisnt Marlon's Wailord and won, but was defeated by his next pokemon Mantine. It next appeared in BW105 where it was used in the first round of the unova league agaisnt Keno's Eelektross, it won in the next episode by using pin misile in Eelektross's mouth. It was later seen in BW106 defeating an Amoongus giving kotetsu his victory in the third round.