Elsa kissed King Mordrak on the lips but she did not close her eyes. She watched his reaction closely while still trying to pull his hands away from Milda's neck.
Fortunately, she was in luck. The grip of his hand on Milda's neck loosened, making Elsa feel relieved. 'Finally,' she thought.
She was about to pull away from Mordrak when he closed his eyes and tilted his head at the same time. In addition, the hand that was once latched on her aunt's neck flew to her head while his other hand landed on her waist, holding her in place.
She felt his lips parted and he started kissing her back causing Elsa's eyes to widen in shock.
She had no intention of 'really' kissing King Mordrak and never in her wildest dream did she have imagined doing that to other men other than Chris.
But she had to do something because the demon king looked like he was in some kind of trance and nothing could stop him from killing Princess Milda.