Final answer:
Abigail is considered a villain because she plots against the protagonist, manipulates other characters causing harm to innocents, and shows no remorse for her actions.
Step-by-step explanation:
Circumstances that point to Abigail as the villain in a drama are multifaceted. First and foremost, the fact that she plotted against the protagonist highlights her design to undermine the main character, often through intricate schemes. Secondly, she manipulated other characters by using emotional, psychological, or situational leverage to bend them to her will, which is indicative of her devious nature. This manipulation is particularly villainous when it causes harm to innocent people, which shows a lack of moral integrity or empathy. Finally, a hallmark trait of a true villain is displayed when she showed no remorse for her actions; an unrepentant attitude towards the chaos and hurt caused signifies a malicious character.