With five hours of indirect sunlight (dusk/dawn), there are few plants that would survive long-term. Many plants (including most food crops) depend on photosynthesis. Thus, your people probably aren't going to be eating a lot of home-grown wheat bread. However, there are a lot of edible plants, roots, and herbs that will grow in low light levels.
Animals will be similarly challenged. They either eat plants, or they eat other animals that eat plants. In other words, animals would have a tough time, too, if they are confined to the dark area.
Without direct sunlight, if the region is small, its weather will be dominated by warm air (and possibly water) currents from outside regions. If the region is very large, it could get quite cold indeed. If that's the case, the cold temperatures will obviously present additional challenges to plant and animal survival.
What about humans?
Since your humans named something "Ghafir's Spear", I'm assuming they have at least discovered basic tool-making (spears). Such humans would probably have good survival prospects, and would develop the skills to adapt to a dark environment reasonably well. That would probably include "importing" food from beyond the dark border and/or cultivating low-light crops and animal herds.
On a physiological level, humans can survive in the dark just fine, as long as we have food, clean water, and can stay warm (in other words, the same requirements in sunlight!). Importantly, the same is true for many animals. The reason animals would die off would be because they lose access to food sources (or perhaps if the weather is too cold—see above).
If the animals can roam into "light" areas to hunt or graze or have help from the humans, most animal species could survive indefinitely, in spite of the dark. Given the choice, however, many animal species might migrate to areas with sunlight because the hunting/grazing is better there.
Vitamin D deficiency
Exposure to sunlight (specifically, UV-B radiation) on our skin actually causes our body to produce Vitamin D, which has beneficial effects. Your humans (and possibly some animal species) might experience some Vit-D-deficiency-related health problems, such as suppressed immune systems, depression, and bone diseases. However, they might find other (dietary) sources of vitamin D (even by accident), and the limited sunlight they get might be enough to produce sufficient vitamin D if they spent enough time outdoors.
What if the humans venture into the sunlight?
It depends how long they have been in the dark, but probably not much would happen to them. They might be dazzled by the sunlight, although indirect strong daylight isn't that much different than looking into the flames of a bright campfire. If an entire society has been isolated in the dark for many, many generations (I can't even guess at a reasonable number) with no outside genetic contribution, their eyes and skin (melanin) might have adapted somewhat—they'd likely be rather pale-skinned—but that would take quite some time, and exposure to sunlight still wouldn't be very harmful. At most they might suffer some temporary/partial blindness and a nasty sunburn if they don't take precautions. If they shield their eyes, wear long sleeves, and a wide-brimmed hat, they'll probably be fine.
Is such a place scientifically feasible?
As you describe it, no, not really. The closest we have on Earth: as you get nearer the poles on Earth, there will be days of the year where the sun never rises. However, it is necessarily the case that in the summer, the sun never sets.
I'll discuss some other options:
If you had a planet that was tidally locked with its star, there would be a dark side (night 100% of the time, almost certainly very cold), a light side (day 100% of the time, and probably very hot), and a middle zone that remains partially lit and warm-ish. However, I don't think that fits what you want, because the planet wouldn't have "days" in the conventional sense of sunrise/sunset at all, and your semi-dark "region" would be a geodesic ring around the entire planet.
You then asked about a perpetually "misty" region. While I don't have a good answer for you on how that might (realistically) be achieved, there are a number of ways you could have a "dark" region:
- Underground. Pretty obvious, so it's probable you've already thought of this and discarded it for some reason.
- Heavily forested. The advantage here is that it solves the plant/animal problem as there are many species adapted to live under the canopies of dense forests.
- Magic. You did list a "magic" tag, so your last resort is perhaps some powerful wizard (or whoever wears the magical pants in your story) who throws a spell/curse/etc. on the entire region, condemning the inhabitants to live in misty, shrouded darkness for 19 hours of the day.