Triggered by Angela's mention, Ethan suddenly remembered that indeed, Xiangwei had a "Succubus Queen" by his side. However, the contract signed was reverse; Angela had sealed the succubus in a jar, and during the collapse of the bottomless abyss, in order to make Xiangwei take her and escape, the succubus was forced to sign a humiliating contract.
As long as Xiangwei is alive, she belongs to Xiangwei.
The last time Ethan heard news about Angela's sister, Xiangwei cleverly utilized the demon's linguistic genius, deploying her to handle business between the consortium and the sub-humans, which included those primitive beastmen who were not very civilized. According to Xiangwei's disclosure, the succubus's latest plan was to wait until her natural death to automatically dissolve the contract.
This reverse contract is a great humiliation for demons, and it's no wonder Angela's sister concocted such a story for her.
