Race: Elf
Class: Assassin
Subclass: Hunter
Guild: Silver Sword
Name: Nakayama Masashi
Age: 16
Birthday: July 27, 2002
Occupation: High School Student

William Massachusetts, also known as Eyes of Mystery William, is the guild master of Silver Sword guild. He was invited to be a member of the Round Table Alliance but declined, stating that its goals had nothing to do with him and his guild.

(Source: Log Horizon Wikia)