Shounen wa Kataki ni Koi wo Suru

A country in an unnamed continent—Shuang. On a dark night, a boy named Hao infiltrates the capital residence of the prestigious and noble Wu family wielding his blade against the family heir, Yanghua. Because Hao's precious savior, Feng, was betrayed by his lover, Yanghua, Hao decides to get revenge on Feng's behalf. But Yanghua offers an unexpected proposal! With his romantic rival, the man he hates to death, love begins to blossom?! A Chinese-style romance period drama between a natural scamp and a single-minded boy is about to begin!

(Source: Kodansha, translated)