Complex sentence: Also, tetsu announced that he changed his stage name to "tetsuya" and released his first artist book, which ranked number six among the Talent Book Charts, while featuring early live pictures and a 30,000 character interview with the bassist.
Split into simpler sentences: Also, tetsu announced that he had changed his stage name to "tetsuya" and released his first artist book. This book, ranked number six amongst the Talent Book Charts, featured early live pictures and a 30,000 character interview with the bassist.