Dead Winter RPG

Nobody knows how it happened, nobody knows when it occurred or how long it was going on. First, it began as a slight change in temperature, almost imperceptible. Then the winters began to last longer, they became colder, slower, until after a couple of years the world simply plunged into the deadliest and longest Ice Age in history. Agriculture died, hunger hit hard, governments fell one by one, some faster than others, but all fell. Humanity was losing against nature, which little by little began to take its toll of decades and decades of global pollution. The world had been enveloped in an eternal icy gloom. People took refuge wherever they could, many underground, others in the mountains or where the cold didn't hit so hard, caves, government and army bunkers, communities began to emerge in the decline, underground settlements, bunkers that were classified as absolute salvation, basic products like food and water became a luxury, and plant-based products and vegetables became so rare that they were thought to be a myth of the old world. But the cold wasn't the only enemy. From the white gloom were born cryptid creatures, humanoid beings that survived the cold, and more dangerous animals. Beings thought impossible began to emerge from the Earth. The surface was a dead zone, and being underground was the only hope. The survivors began to call the surface the Snowy Hell. Nobody went out, nobody looked up, and those who did venture out only did so in extreme cases. No one expected them to return alive. The world had been submerged in eternal snow for 150 years, where the remains of what was once modernity are simply buried in the snow.

The survivors never surface; they survive as best they can in their settlements.
-Cryptids and other things:
Yeti: creatures with bluish skin and thick white fur all over their bodies, they are large and robust, they hunt humans and are very territorial. Winter wolf: a much larger and tougher species of wolf, with white fur, they are wild and attack anything that moves.
-Cannibals: cannibalistic human groups are cruel, sadistic, and have no interest in human life.
Winter Owl: a species of owl 1.80 meters tall, with light gray plumage, they attack anyone who approaches their eggs. Apocalypse Vultures: Vultures 3 meters tall, with black, dark gray or white plumage, they hunt people and their feathers are used to make special arrows.
-White Demons: humanoid beings with pale skin, they are quite aggressive and bloodthirsty, they eat human flesh and live in caves that have no human presence, they sleep during the day and come out at night to eat.