Li Kai travels through the wizarding world and is bound to the Great Collector System. As long as he collects magic items, he can get various rewards.
“Congratulations to the host for obtaining the rare collectible [Hogwarts Admission Notice] and a drop of [Demon Blood] as a reward.”
“Congratulations to the host for obtaining the perfect collection [Yew Wand], and the reward is [Grandmaster-level wandless casting].”
“Congratulations to the host for obtaining the legendary collection [Magic Stone] and the reward [Grand Master Alchemy].”
…
A few years later, the entire wizarding world was shrouded in the glory of Li Kai.
Hermione: “Kyle is the most outstanding wizard. I have admired him for a long time.”
Cassandra: “I admit that I like Kyle, but so what? How many witches in the entire wizarding world can resist the charm of that man?”
Voldemort: “Damn! He actually wants to collect my skull. I will never let him succeed!”
Dumbledore: “Kyle is the most powerful demon king in the world, and I am convinced of his magical attainments.”
…
