I dont think it could be Cecil the culprit, she was the one who suggested to ryan hyung to not let Kyon goes away, furthermore she tried to clarify Lucaon doubts on Kyon, maybe she is just really a nice person after all, not like ryan whom acts completely nice outside but he would kill you if you were a treat to him.
Or maybe it's just that it's actually Ryan that she's targeting, and not Lucaon...
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Nooooo our big boy is just lonely not mean or an assassin, hope that we are completely wrong, i dont think if i can handle this drama :( but if it may happen, yuyang be a fuckin man and stay at lihuan's side D: