Here's your antagonist:

• Name: Daphne (plays on the dainty damsel stereotype, a contrast to her twin's strength)
• Personality: Daphne is whip-smart and uses her intellect to belittle others, especially her twin sister. She comes across as sophisticated and cultured, but it's a facade to mask her insecurities.
• Motivation: Daphne feels overshadowed by her twin's physical strength and achievements. She resents the attention her sister gets and tries to undermine her at every turn. Her jealousy compels her to prove herself superior, even if it means resorting to underhanded tactics.

Daphne: you look so ugly