The Time-Traveling Girl Fights Against the Original Owner's Sister

I am a time-traveling woman, and I thought it would be a battle of wits and courage with a vicious female supporting character, but what she did was beyond my expectations. Not only did he come to my rescue, but he also always protected me. What's going on? ? Later, he even sacrificed his life for me. "Sister, I'm sorry..." "It's okay, I know you didn't mean it."