This is only my opinion. You are free to disagree and make your own list. Note: This is not "strongest mask" thread. Impact is more important than pure combat skills IMHO.
This is it: (first one being the deadliest and going down from there)
1.

Easily the deadliest IMO. If it would block my path I woudl think twice before battling it or trying to evade it unless I'm really well equipped.
Question: What happens if you try to evade it but fail? Normally you take stamina damage, but this one doesn't have any. You can just try to flee again and again? (assuming you passed to horror check after failing the evade check)
2.

Probably the best gate guardian in the game. Dark Young who?
3.

If it comes early it can really cause havoc. And disposing of it is no easy task; -3 evade check is very difficult and even after that it's not like he's your average Cultist...
4.

I would really rather not fight that thing at all, meaning it will forever hinge on the monster limit (unless he's in an expansion board, although there's still a slim chance for aquatic movement)
5.

If that thing pops out during an encounter and you're a spellcaster, you better start packing and start a new investigator.
6.

While you would probably won't kill that thing in combat, it is easily evaded.
7.

Same, although this one is even easier to evade and easier to battle against.
8.

Very underwhelming, very easy to kill.
9.

The fact you need to use lore instead of fight means little. Even if you're not a spellcaster it doesn't matter as weapons still work against it.
10.

By far the weakest one. Without Blackest Night it's cannon fodder. With it, it will still probaby hang out in the sky for most of the game, not to mention an environemnt can easily replace Blackest Night. Your only concern should be encountring it during an encounter with Blackest Night in play, but even then he's not so hard if you're well equipped.
These were my ovservations. Feel free to discuss.
p.s. anyone knows the answer to the question asked at the start of this thread?


