As of the december patch, all "killer" and "circle" effects now add an automatic paralyze-like effect to the referred-to mob type. It gives a "[mob] is intimidated by [player]'s presence" message. Note that dragoon-type mobs can use this against dragoons' wyverns also. Killers and Circles and Paralyze can all be stacked. Circles last 1 minute and can be recast every 10 minutes. This information is from Squaresoft's patch notes (except the stacking part, that's from my experimentation).
Well, only "demon" like thing I can possibly think would be a deamon below 45 would be the dragons (for the missions) and those strange hounds here and there.
The rank 3 dragons are, actually, dragons; they're intimidated by ancient circle, but not warding circle (or the DRK or PLD circles).
An interesting thing to note, btw, are that demons and dragons are mutually opposable- a dragon will have a 'demon killer' effect, intimidating demons; a demon will have a 'dragon killer' effect, intimidating dragons... so if you have a DRG in your party, and your fighting demons, his wyvern will stand a chance of getting intimidated, and not attacking.
If somehow you can get the wyvern to tank (good luck talking the DRG into that), the demon stands a chance of being intimidated by the wyvern.
Really only useful to soloing DRGs that pop Super Jump on a demon. But nice to know, none-the-less.
the samurai have the interesting quality of disabling and making the Demons of the Shadow lord intimidated and afraid. This strikes me as amusing.
Anyway, you have this ability very early on as a Samurai, but you won't use it until way later in the game when you are strong enough to tackle the Shadow Lord's choice servants, the Demons. Oh yeah, and the official name is "Warding Circle"