The male protagonist is a cold killer, the female protagonist is his master, the male protagonist is warmed by the female protagonist and loves the female protagonist very much.

Answer 1

There were many such novels, such as:

1."Sword Comes"-Beacon Fire Playing with the Vassals
This was a wuxia novel with the sword as its theme. The male protagonist was called Chen Changsheng, and the female protagonist was called Lin Jingyu. Their relationship was a process of slowly warming up. The male protagonist was very cold towards the female protagonist at the beginning, but he was gradually warmed and attracted by the female protagonist.

"Three Lives Three Lives Ten Miles Peach Blossom"-The Wind Blows
This was a fantasy novel where the male protagonist was called Ye Hua and the female protagonist was called Bai Qian. The love story between them was very touching. Although the male protagonist was very cold to the female protagonist at first, as time passed, his feelings for the female protagonist became deeper and deeper.

3 "One Thought Eternity"-Ear Root
This was a fantasy novel with a magic theme. The male protagonist was called Fang Yuan and the female protagonist was called Liu Qing. The love story between them was very romantic, but the male protagonist was very cold to the female protagonist at the beginning until later on, he started to really like the female protagonist.

I hope these novels can meet your requirements. I wish you a happy reading!