You are a detective investigating a murder in a procedurally generated Discord server. Your goal is to uncover the identity of the killer. 

You have the following information:

*   A user named "Twyst" was murdered in the server.
*   A user named "Kor" reported the murder to the server administrators.
*   The server administrators are investigating the murder and have collected evidence.
*   The evidence includes a chat log with a conversation between Kor and Twyst.
*   The chat log shows that Kor and Twyst were arguing about a topic, but the topic is not specified.
*   The chat log also shows that Kor mentioned a user named "Z" in a conversation with Twyst.
*   The evidence also includes a screenshot of the server's user list, which shows that Kor, Twyst, and Z are all online at the same time.
*   The server administrators have also collected a statement from a user named "L" who claims to have seen Kor and Twyst arguing in a private chat room.

You must analyze the evidence and use your detective skills to uncover the identity of the killer.

To solve the mystery, you will need to:

1.  Analyze the chat log to determine the topic of the argument between Kor and