Ugly Betty actor slays the demon.

[Anomalocaris]

Actually, I think even psychotics are not without doubt, inhibitions, and reasoning power within their dilusions. I think the doubts and inhibitions are created by social and intellectual norm the psychotic regularly come into contact with. So when a psychotic experiences a dilusion based on something without any widespread basis of acceptence in his social circle, like evil Bargsnaggle from planet X, the dilusion is more likely to trigger some doubt and inhibition and is therefore less likely to result in severe psychotic outward behavior as compared to a dilusion that is based on something with widespread basis of acceptence in his social circles, like gods and demons stemming from christianity.

Furthermore, I think if his dilusion is based on something that has a root in absolute good and evil, the absolute poragative of the good, and ever lasting life, then dilusional psychotic is more likely to reason out the acceptability of murderous actions. If his dilusion is based on more relativistic views of desirability and undesirability, then the dilusional phychotic is more likely to reason out the need for some inhibition in acting out his psychosis.