Rungholt

Rungholt is a large, nowadays pretty much uninhabited island north of Kashura and The Shattered Sea.
For over a thousand years it was the homeland of The Gray Giants, a particular branch of The Hominid Strain, known for their imposing stature and snow-white to stony gray skin. This has changed relatively recently with the cataclysmic eruption of The Vulspar, a massive Volcano that used to be located in the center of the Island, its heat and eruptions providing fertile soil allowing life and civilisation to flourish even this far up in the frozen north of Kashura.
Yes, used to, for the eruption was so catastrophic in power and scale that it leveled the entire mountain, eradicating everything that surrounded it.
The eruption killed over 90% of the island's population and the rest fled shortly after with whatever means they had available to them. This all happened only weeks after The Starfall (0 SF), an event so significant, it would usher in a new age in a part of Kashura so distant to Rungholt, few of its inhabitants had ever even heard of it.
Rungholt would however not be the only place affected, as the eruption of The Vulspar would send out shockwaves and earthquakes which could be felt from as far away as Shaoshen. Earthquakes would shake the entire coastal region of The Shattered Sea for hours, even days, and ashen clouds would darken the skies for weeks to come. Many of the people settled along the coast of The Shattered Sea genuinely thought the end times had come and fled further inland, leaving entire towns abandoned to this day.
For the ones that stayed, fate would not bode well either, as what would follow these events would be the largest invasion of The Northmen, another term used to refer to The Gray Giants, they had ever seen. As dozens and dozens of ships would appear from behind the horizon, carrying not hundreds, but thousands of northmen to their shores, followed by clouds of ash, smoke and fire.
It would be this migration, which would set in motion the collapse of the trade networks of The Shattered Sea.
For a few decades nothing was known of how Rungholt had changed, until one brave hominid explorer, a Gray Giant by the name of Einhart Tolfarsson, made the journey back to the ancestral homeland and returned to report his findings.
A new Mountain chain, The Ashen Peaks, now formed a ring around the old site of The Vulspar, seemingly pulled from the ground itself, the force of the eruption molding bedrock like clay.
In the place of The Vulspar a new lake, The Burning Sea, seemed to have formed right in the middle of the island, its waters running red and black like a mixture of blood, soot and embers and smelling of rotten flesh and brimstone.
The fertile valleys which once surrounded The Vulspar had given way to a desolate icy desert, blood red dust and ash mixing with snow, while the many trees in the area had lost their leaves, turning charcoal black yet somehow still standing, with veins of amber running through them.
Finally, the Island was now inhabited by new, strange flora and fauna. Unholy creatures, mutated and malformed, as well as ashen husks of the wandering dead now roamed the landscape.

Climate:

While it used to be much more diverse before the eruption of The Vulspar, the climate of Rungholt now has normalized to what is expected of the region. Most of the island is covered by ice and snow all year round, with temperatures rarely rising above -20C (-4F) and dropping as low as -80C (-112F) during the coldest winters in the harsh season.
The lands surrounded by The Ashen Peaks still are a good bit warmer than the frozen wastelands surrounding them, though temperatures there are still usually far below freezing even on the best of days.

Population:

The hominids which used to inhabit Rungholt have mostly died or fled the region. While there is no way to truly know whether or not there are still people living here, eking out an existence in the frozen wastes, for all intents and purposes the island is now uninhabited.
The people which used to inhabit Rungholt are The Gray Giants, a particularly strong and large branch of The Hominid Strain. They used to live in the fertile valleys surrounding The Vulspar, farming, building and warring with one another just like any other society. They sometimes went on raiding missions, plundering and extorting the people living along The Shattered Sea. In the beginning this would usually only happen with the appointment of a new chief or if that year's harvests and hunts were insufficient to feed themselves, but with the millenia they grew more and more common.
Most of them used to follow The Ashen lord, a God of fire, war and survival, which was said to dwell in the fires of The Vulspar. Used to, because he killed most of them, and of those who lived to tell the tale, many lost their faith. The Ashen lord was never a particularly kind god, he frequently ruined harvests and brought harsh winters, but it was always presumed to be to their betterment, to bring out the best in them, to encourage them to reach for ever greater heights. Of the people that survived, around half still follow The Ashen lord, presuming that they had grown weak and content, which was the reason for such drastic divine punishment.
The Survivors of The Eruption mostly settled around The Shattered Sea, either living in harmony with, or taking from the people that inhabited the region before them, depending on the place. The largest collection of Gray Giants nowadays is the city of Kallmark (see: Griselderyn), on the eastern coast of The Shattered Sea.

Landmarks:

The Ashen Peaks
The Burning Sea