* Is unable to perceive an [[angel]]'s true form without his [[meatsuit]] getting obliterated in the process.<ref name="four10" />
* Is vulnerable to [[devil's trap]]s, [[holy water]], and [[salt]].<ref name="four16" />
* Can be killed by the [[First Blade]] if the owner is possessing the [[Mark of Cain]] (This is only assumption as in [[9.11 First Born]] it is said that the Blade can kill anything)
* Higher level angels such as [[archangels]] can presumably harm, but not kill, Alastair
* More powerful demons such as [[Abaddon]] and [[Cain]] can harm him and Cain can probably kill him
* [[Leviathans]] can kill angels and therefore can probably kill him
* [[Lilith]] is able to kill him as she was the first demon in creation and he was the second
==Episodes==
