Give the name of the No.1 character in the credit list from the highest rating thriller movie.
No.1 character in the credit list refers to creditOrder = '1'; highest rating refers to max(rating); thriller movie refers to Genre = 'Thriller'
SELECT T2.`Character Name` FROM movie AS T1 INNER JOIN characters AS T2 ON T1.MovieID = T2.MovieID WHERE T2.creditOrder = '1' AND T1.Genre = 'Thriller' ORDER BY T1.Rating DESC LIMIT 1