许汜 / Xu Si (Late Han)
许汜 / Xu Si (Late Han) enters the wiki through Hanji 974 as one of the officials who secretly discuss betraying 曹操 while Cao Cao is away attacking 陶谦 in 徐州. The episode names him with 陈宫, 王楷, and 张超 in the group that moves the plan toward 张邈.
The source does not give Xu Si an independent biography. His wiki role is as evidence that the Yanzhou rupture was not only Zhang Miao’s private decision; it involved a local official-adviser circle willing to invite 吕布 into 兖州.