Lan

 Lan is a person with no moral compass who does not distinguish between right and wrong nor between strategy and arrogance. She is a person entirely lacking in empathy and is the epitome for every one of the seven deadly sins. 

She has the least or lowest scruples in the series.  At times when even other 'villians' told her to slow down, be cautious, or stand back she ignores them and does whatever she wants.  She is a burden even to her own villianous bad guys and is literally no one's friend.  She does not even care nor show concern for her own family.  This girl as as low as you can get when even other bad guys grind their teeth at her.