Zhan Luo was taking his evening walk at the top of Kunlun Mountain when Ruo Yin's question about why he helped her came to his mind.
"Even after all these years and with her memories wiped, that girl is still the same. She just dives headfirst into the water as always," Zhan Luo sighed as he said that to himself as he sat on a rock beside the waterfall that was on top of the mountain. While he was enjoying the sound of the waterfall and the calm scenery that Kunlun Mountain always had he also started to reminiscence about the past.
Five thousand years ago, the clans were at peace. But that changed when the old Demon Lord died under mysterious circumstances and the young You Xie rose to power. The immortals were not sure that having such a young deity as the Demon Lord was the best decision, yet there was no one else to fulfill the role, so everyone just accepted him with doubt.
After a few hundred years, You Xie proved to be a charismatic and capable leader. The Demon Clan seemed to grow and prosper, and there were no conflicts, so the other clans started to lose their suspicions towards him. That is when words spread that he was planning a revolt toward the Sky Clan.
The Sky Clan knowing about it sent some spies to check what was the Demon Lord's plan. It did not end well. You Xie decapitated the spies and sent their heads back to the Sky Clan. The charismatic and calm facade that the Demon Lord showed to the others started to crumble and his true intentions started to show. He was a cruel and ambitious one who was willing to destroy anyone or anything to get to his goal. He was not comfortable only being the Demon Lord. He wanted to rule over the Immortal Realm. He wanted to be the Sky Emperor.
Then, the war began. Zhan Luo remembers that many innocent lives were lost, including Ruo Yin's parents. The Demon Lord, himself, killed them. Zhan Luo did not know the cause, but he remembers that Ruo Yin saw how her parents were killed. There was so much hatred was in her eyes that it matched the Demon Lord's. "That girl even stabbed me," Zhan Luo thought.
Zhan Luo also remembers how her parents in their last breath asked him to protect their daughter. To erase her memories. They did not want their daughter to become cold and ruthless as the Demon Lord. Before he could ask them, how they were sure that You Xie would not kill their daughter, they passed away. Zhan Luo accepted their pleads and quickly stopped the young Ruo Yin from attacking the Demon Lord.
Soon after, the Demon Lord was successfully subdued by the Sky Clan warriors, and Zhan Luo erased Ruo Yin's memories of the incident. You Xie pleaded for the Sky Clan forgiveness. The Sky Emperor forgave him and the Demon Clan with the condition that they were going to be punished with the red tattooed mark on their necks which would activate restrictive magic and subdue their powers. Leading them to be just a bit more powerful than a simple mortal.
Zhan Luo later heard that Ruo Yin was named princess of the Demon Clan. He knew You Xie was planning something, yet, he just was not sure what. On the day of the annual reunion, Zhan Luo finally understood You Xie's motive for naming Ruo Yin as a princess. He was going to use her. After five thousand years, You Xie was putting his revenge plan in motion.
Obviously, Zhan Luo did not alert the Sky Emperor that You Xie was maybe planning something, instead, he decided to marry Ruo Yin. He knew You Xie will never deny his request. What was better than sending a spy to check 24/7 on the War Deity himself. He even knew that You Xie will most likely tell Ruo Yin another version of the story so that Ruo Yin will antagonize him.
"After five thousand years, we are going to cross paths again. Can this be fate?"
Zhan Luo was looking forward to their wedding tomorrow. He knew that there were going to be a lot of hardships in the future for both of them and that, eventually; he needed to tell Ruo Yin the truth. Yet, tomorrow would not be that day. He wanted to see what Ruo Yin's part in You Xie's scheme.
As he was preparing to return home, he just hoped that erasing her memories of that day was not a mistake.