Anyone know the longest someone has lasted in a staring contest? 
But realistically how do you handle them in a CR description versus WHO Lore description?
First when you look at them they are harmless so any PC who tries to avoid blinking will have to make some sort of check to avoid such eventually. Second a crafty PC can declare that they simply close one eye at a time opening each one alternating by winking instead of blinking. Sure eventually they might have to turn a corner and lose sight but if they know of the weaknesses they can negate the threat until another character can improvise a mirror or make another construct or undead (though it must be sentient I guess) to look at it.
They turn to stone when you look at them, but in D&D stone is destroyed all the time. So in order to avoid easy destruction maybe you would have to make them out of Adamantite or declare them indestructible when looked at.
They move so very fast when not looked at but they do seem to have momentum constraints. They can clear a room in a very quick speed but they seem to only get about normal movement in a blink and sometimes even less than that. So since their speed is fast but unknown how do you rate it?
Then if you look at them for too long they ingrain themselves in you brain so you have to be careful. Anything that captures the image of an Angel becomes an Angel so smart players who bring mirrors can keep Angels at bay indefinitely by having them look into it. Creating illusions of Angels would theoretically create more of them as well. Another thing that works in this fashion is shadow magic creating shadows so they might be linked to the plane of shadow. This is not so bad as it is similar to a Vampires Domination and as keeping your eyes closed prevents the Angel from taking hold, but it is ultimately irreversible after a point and requires time to develop fully so that might make it more of a disease that continues to trigger over rounds as long as the eyes stay open. Also the fact that illusions can create them could lead to some interesting plots if someone misuses such power.
They don't kill but drain your possible future time by shunting you into an alternate timeline but Ravenloft does that through the Dark Powers and so it is possible that you could find your way back if the Dark Powers willed it but in the show it was tantamount to a death sentence as you were not supposed to be able to get back. Does time traveling no longer work on the character except through exceptional circumstances, and if it does, then does the Angel realize the change to their food supply? In the show they just cause you to vanish from your current timeline and appear in another. This however is not caused seemingly by simple touch as the Angels have grabbed some people and been seen by others in time to talk to them since they cannot free them, so I guess it could take a full round action. While this does not kill the character this eliminates them from play for the foreseeable future so this is similar to a death effect.
So to summerize
-Invulnerability or near such possibly listed as an epic or high DR only vulnerable to magic.
-Gaze attack with a will save vs Domination disease Death Effect creating an Angel in the mind of the victim but may be negated through closing of eyes.
-Images of Angels become Angels.
-Touch Based full round time shifting Death Effect but only when not watched so perhaps shorter or longer depending upon observers.
-Extremely fast movement.
-Weakness that they cannot move while something (Sentient) observes them at all.
I don't know how to calculate this CR? Anyone got any ideas?
