Chess Piece
The black-robed figure was none other than Rayna. Since she was the only one in the Battle Maiden Sect with Poison Qi and had also mastered the art of concealing her aura and many other complex techniques, she was perfect for the job.
In the Battle Maiden Sect, Rayna was held in high regard by Aelina due to her exceptional talent and willpower. However, she wasn't well known, both in and out of the Sect. Those who did know her were either her fellow disciples or six feet under.
When Aelina had presented her with the task of infiltrating the Toxic Blade Sect and making them suffer, she accepted without hesitation. Their conversation, shrouded in secrecy, showcased only one aspect clearly: Aelina and Rayna's mutual aspiration for the ruin of the Toxic Blade Sect, and for good reason.