In a cold country ruled by a hard-hearted king, three close rogues commit to a secret quest to find the girl from the prophecy so she could fulfill her destiny as the second Follower and help put an end to the dread of the emerging NightSouls.
Since this doesn’t seem to be about taking down the king. I would drop the part about the “hard-hearted king” and replace it with what bad thing will happen if the NightSouls emerges.
Something like this:
When the land is threatened (With this bad thing) because of the emergence of the NIghtSouls, three rogues go on a quest to find the girl from prophesy, in order to save the land.”
I agree with Richiev.
Personally, even in fantasy loglines, I try and avoid using names of creatures/characters/things unless it’s really clear what they are. NightSouls is interesting but without understanding what the NightSouls are and what their appearance means I would probably recommend using a description of them that is more relatable. Same goes for the whole “Second Follower” thing. It means nothing without the context of the story and a reader of a logline won’t have that.
As Richiev asks in his second comment, why not one protagonist? This doesn’t mean you can’t have three rogues still but having one central protagonist creates a stronger emotional story that the audience can empathise with as they are only (largely) dealing with one perspective. (hope that makes sense). Most ensemble films still have a central character, like leader of the group – Danny Ocean in Ocean’s 11, Gordy in Stand By Me, etc.
Summing up, I think you need to give us the stakes (what’s set to be lost if they fail), scrap the king bit, focus on one central protagonist (and give him a characteristic that hints at his emotional arc), and streamline the whole girl/prophecy bit so it reads in a succinct and effective way.
Hope this helps.
Concur with mikepedley85 about the problem of using terms for a fantasy world that right now exists only in your mind.
“Second Follower” — what is that supposed to mean? I have no idea what the dramatic significance of such a character. “NightSouls” — who are they and what makes them so bad they must be defeated?
Characters and situations should be introduced in terms that the typical logline reader should already be familiar with. Save the terms unique to your fantasy world for exposition in the script.