It seems that anyone can join the Xanathar Guild, which, despite its name, doesn't have official guild status in Waterdeep.

Rumour is that before membership is granted, an applicant must pass a test that often involves the perpetration of a serious crime.

Xanathar Guild support could comes in these ways:

• Any member given an assignment might receive a monstrous bodyguard or assistant.
• The guild grants access to secret tunnels and safe houses underneath Waterdeep.
• Xanathar might send an assistant to help an up-and-coming guild member.

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