there's something really unsettling about portal and portal 2's rattman dens
here's a character who, if you don't read the tie-in comic, you know absolutely nothing about. he lives in the walls and creates these creepy murals and cryptic writings. he's watching you wherever you go, presumably, but you never see him, never know what his motivations are. but he knows about you. he idolises you, from the murals in portal 2.
and yet in portal 2, there's no way he can still be alive. the facility's in ruins, you've been in stasis for a long time. but you can tell he was looking out for you - he's on your side, he wants you to succeed. but he's gone. and you'll never meet him.