Imperial Lineages Suppression
During the Emperors Era the Divine Beast Realm's disciple was a powerful contender for the Heaven's Will, but eventually he was defeated by Hong Tian. Unconvinced by his defeat, the Divine Beast Realm encouraged all the sects in the Stone Medicine World to ambush Hong Tian who had yet to ascend to Immortal Emperor. All the most powerful lineages in this world were involved in this terrible ambush, including the Alchemy Kingdom, the Jianlong Clan, and the Beastmaster Citadel as well as other imperial sects.
This ambush enraged Dark Crow, who sent his army to the Stone Medicine World. The army swept through the world and eventually destroyed the Divine Beast Realm. After that, Dark Crow forced all other lineages that participated in the war to made a blood oath to never show themselves in the world again.
Alchemy Kingdom have a marriage pact with the Huangfu Clan that has been going on for several generations; Huangfu Clan has many relatives in the Kingdom, and all of them are great characters in the imperial families.