Complex sentence: Although Seifer is a gifted warrior, he has a stubborn, arrogant, reckless and unpredictable nature, and although he has taken the SeeD exam multiple times, he has failed on every attempt.
Split into simpler sentences: Although Seifer is a gifted warrior, he has a stubborn, arrogant, reckless and unpredictable nature. He has taken the SeeD exam multiple times, he has failed on every attempt.