Complex sentence: A blader who often uses tricks to win battles, as well as to scratch the beys of his opponents, Tetsuya believes that friendship is usless, based on a past experience in which he was betrayed by his best friend.
Split into simpler sentences: A blader who often uses tricks to win battles as well as scratch the beys of his opponents. He believes that friendship is usless due to a past experience in which he was betrayed by his best friend.