Who Is This Character? By Nicholas Wong

My character is a strong and fast warrior who works best alone.
      He is a good pilot and is very impatient unlike his friends.
      He has dark brown hair and light brown skin. He usually wears black clothes without armour.
      He was very kind but then he turned evil and betrayed his friends. After he turned evil, he lost his intelligence and became clumsy.

                               Who am I?