Complex sentence: He returned to Japan after his release from the WWF, competing in Japan's premier promotion, New Japan Pro Wrestling (NJPW), where he used his American Dragon persona, and donned a red, white, and blue mask reminiscent of a dragon.
Split into simpler sentences: He returned to the country after his release from the WWF, competing in Japan's premier promotion, New Japan Pro Wrestling (NJPW). In NJPW, he used his American Dragon persona, and donned a red, white, and blue mask reminiscent of a dragon.