Transmigrated as the Shadow Guard of the Gloomy Prince

I transmigrated as the shadow guard of a Gloomy Little Prince. According to the plot, years from now, he will become a crazed tyrant because of his unrequited love for the female lead, eventually meeting his end at the hands of the male lead. And every shadow guard by his side will be beheaded along with him. To save my life, I decided to beat the female lead to the punch and shower him with warmth first. When the female lead tried to give him candy, I had already stuffed his mouth full of it. When the female lead wanted to bandage his wounds, I had already wrapped him up like a zongzi. When the female lead worried about his insomnia and came to chat with him, I had already knocked him...