Yeah I don't know. Karsh never was possessed by it so I don't know what he was talking about. That's weird. I never noticed that before o_O

But it doesn't affect Lynx because he's, in a sense, a living computer. FATE erased Wazuki's humanity and made copy of herself into Lynx. That's why he's called FATE's biological interface (or something). Lynx then doesn't have any animosity or feelings left and just acts on behalf of FATE so he's not affected. He took the sword and put it in the entrance way to the Dead Sea so more people wouldn't go in there and cause all kinds of trouble. Since the normal defense barriers were down this was kinda the only way to make sure people wouldn't get through.