I think its one of the highest toggles in the game, but I thought it was less that Choking Cloud and Artic Air.
Just checked Nofuture and it lists it at 2.6 with CC as 2.03 and AA as 2.08........... It seems wrong to me because the other two toggles are more crippling and on alts that dont have all the DA armours to run too. Hmmmmm
"Well, they found my diary today.
They were appropriately appalled
at the discovery of the eight victims
They're now putting it all together.
Women wrapped in silk
with one leg missing
Eight legs, one body, silk,
spider, brilliant!"
AFAIK all of the DA toggles use a hideous amount of end, and it's due to the fact that they are so very effective. There have been quite a number of posts asking the Dev's to tone down the insane endurance costs, but sadly these requests have fallen on deaf ears.
@Byrne
Debtmeister General of The Plastic Army & Empire
2.6 seems far too high.
A character with 3 slotted stamina recovers about 2.5 ish.
Previous versions of Hero Builder put it at about the same as the damage auras. These are now about 0.5.
The tick rate for Cloak of Fear is 5s seconds, so the actual end cost is more likely to be 2.6 / 5 = 0.512.
The people who have recently been redoing endurance costs seem to have missed the tick rate information.
It is an expensive toggle, especially on top of the others, but I find that it is worth it.
@Unthing ... Mostly on Union.
0.512 makes a lot more sense
Yeah, Nofuture also has the tick rate of 5 seconds - they assume that people are able to work it out but evidently not 
In hero builder the stated endurance cost of this is 2.6
That seems phenominally high for a toggle (phase shift is only .59 and thats a killer) .. is this a typo and does anyone know the actual cost