Over time it slowly enhances the bearer's physical capacities, increasing their combat abilities and intelligence. The bearer is marked with a flower that glows when the powers activate.
As a side effect, the blood of the person becomes alluring to all Vampires, making them sometimes hard to resist the temptation to drink their blood as their blood smells tasty to them. Both Fan Le Lao and Ge Chen end up entranced by its powers at one point or another after one bite. Another power granted is the ability to retain their humanity in spite of being bitten by vampires numerous times and never become a Vampire.
At the moment, Xi Tai notes that Yue Jian at least only knows how to use the ability as a power up. It has another purpose she has yet to discover. The Sabbat also learns of its actual purpose, while the reveal of the information is hidden for now from the reader of the manhua, Zhao Yan is shown to be deeply upset by the information to the point she cries.
Mei Yue Yin remains in the blood of the Vampire who bit the barer, during the negotiation over Ge Chen's life with the Assamites, this was brought up as an attraction for him to them.
Isis later reveals she intends to take both girls' lives and in turn take everything they have, as she views them as part of her (being clones) and yet not as they lead their own lives. Part of this involves the forced growth of Yue Jian's power gained from the Mei Yue Yin.
Xi Yan's fake SerumEdit
Although it appeared as a glowing flower like the original and even managed to produce the same scent, it did not grant her special powers or immunity against vampires nor enriched the quality of her blood to allure vampires. In the end, she ends up becoming a Vampire when Yi Sai bites her.
- The concept of Mei Yue Yin is very similar to how hunters become Imbued in Hunter: The Reckoning.
- "Mei Yue Yin" means "Fascination" in chinese.
- Both the girls who received the real dosage have the flower on their left side of their chest, for Xi Yan, her flower appeared on the right. The flower remains on the girls with the real dosage but so far appears missing on Xi Yan. Though it was never stated that the flower had to be on a particular side, it was a subtle hint that Xi Yan's dosage was fake when looking back on the early chapters.
|The Demon Hunters|
|Leaders||Hue Ge Lin ● Li Tao ● Yi Shen ● Osiris ● Ada|
|misc. characters||Zhi Yan ● Zhao Yan ● Ling Xue Xiao ● Lin Xuan Chi ● Professor Nam Gong ● Kai Lin ● Xue Jiao|
|other||Forbidden Sphere ● Xiong Shi ● Mei Yue Yin ● Sui Xi Bing Lin|