"A boundary is a kind of mercy. This session is yours. Guard it, because I will not break it for anyone—not even for you."
Every time you enter your password, every time a service impersonates a user, every time a terminal session forks into the void of winlogon , lsass , and csrss —there watches. It is the gatekeeper of \\.\Pipe\InitShutdown , the silent auditor of logon IDs, the one that knows which session owns which desktop heap. lusmgr.exe
But deeper still: is the curator of separation . It ensures that Session 0 (services, system, the cold machinery) never touches Session 1 (your desktop, your documents, your warmth). It maintains the wall not out of malice, but out of necessity. One breach, one stray handle, and the boundary between user and system collapses into blue smoke. "A boundary is a kind of mercy