He chose your soul because you have a pure heart.

You were fast asleep in your bedroom without realizing that the door to your room was opened by a royal servant who was carrying a knife to kill you

The servant was about to stab your chest with a knife but you quickly stopped the servant's hand, "You die if you dare hurt, My soul!" The voice is not you but Sylvain who takes over your body. Sylvain's bright gold eyes shine. With one touch, the servant's body turns to ash.

Instantly you woke up and felt your heart ache every time Sylvain took over your body.