Damian Hart

is the team leader of the USA representative team "Starbreaker, who also works for Dr.Ziggurat at HD Academy.

Big Bang Bladers arc
As HD Academy is shown for the first time, the scientist, and leader of the organization; Dr. Ziggurat is using a device called the "Arrangement System". A boy named Damian is shown inside one of those capsule devices, which is brainwashing, and infusing power from Hell Kerbecs into his body.

After Dr. Ziggurat finished his work on him, he sent Damian to bring Ryuga back to HD Academy, and to test out his new power. At a Beystadium somewhere, he interrupts Tsubasa, and Yu's Beyblade race. He tells both Tsubasa and Yu that he wants to test out his Bey against them, which they accept. Not too long after, an explosion is seen in the background during Masamune and Zeo's battle at the park. Ginga and the others rush to the scene. Upon arrival, devastated, and shocked by what they see... Tsubasa and Yu are majorly injured, and unconscious, along with their Beys which have suffered a devastating disaster as well.