Similar to patrol guards but with a twist.
In Normal world, they are the Soviet snipers.
They run from point to point, faster than the player, but when they reach their point, they are using their gun/sniper so they can't see, BUT they can hear when they are looking down their scope!
In the Fantasy, they turn to a [Idk yet, suprise me]
They are idle in the Fantasy universe, and they don't see or hear. Essentially an object of decoration.
In Nightmare, they are something like Slanderman, tall creatures, pale, and no face. When they spot the player, they run by bending down, using their arms and legs to run, very fast.
Recommendation State Tree for normal
The value for run speed should be changed based on the world the player is on, nightmare is super fast, normal is fast, fantasy is idle.
Unreal engine has a feature for listening, I think we should implement that for when the AI is "looking down it's gun to snipe" and unable the vision. Maybe a Boolean to check if AI is using Gun. If yes, just use ear behaviour, if no, just use vision behaviour. (Only suggestion)
In Normal world, they are Soviet Soldier as snipers.

Soviet sniper in the Battle of Stalingrad 1942 in massive and deadly urban battles, both Men and Women of The Soviet Red Army took part in this great battle as snipers to combat the German 6th army in Stalingrad
In Fantasy, we still don't know yet... tbc open to suggestions
In Nightmare, it's tall and pale, hugely inspired by Slanderman.

Not sure about the slimness, maybe less like a suit, more like demonics? I am still unsure about their vision. Any inspiration from Persian mythology is welcomed