To repay a favor

Is this... an offer of allegiance? Alexander was stunned, and apart from Emperor Kui, who maintained his composure, everyone else looked equally baffled.

The Blood Queen!

While few had ever seen her in action, everyone knew she was an immensely powerful entity. Just because no one had witnessed her abilities didn't mean she had never exercised them. Rather, those who had were no longer among the living. 

Although unspoken, it was common knowledge that the Blood Queen was one of the guardians of the Mist World, her status akin to that of Karin.

"Do you not wish for it?" the Blood Queen asked softly.

"Of course, I do! We at the Fierce Ghost Association warmly welcome your joining!" Alexander promptly nodded in agreement.

"I knew my little brother would agree!" The Blood Queen's face lit up with a smile again as she took her place behind Alexander.