When bears begin hibernation, all of their souls come together to help bring Mathos into the physical world.
When his form is made, winter comes. He brings the land into hibernation for three months and then returns to the other side.

The Hibernation Bringer. Guardian of Bears. Bringer of Blizzards. Watcher of White.

Mathos is described as being a bear whose fur is made of individual ice shards, looking like he is extremely pale blue. He has symmetrical markings across his body. Mathos' eyes are said to be like zircons with glow worms behind them, giving them an eerie glow. On his back are much sharper spines of ice.

Mathos' exact height is not entirely known, but it is said that he is twice the size of a grizzly bear.

It is unknown what he would weigh.

The symbol of Mathos is a sleeping bear inside a kind of snowflake formation.

Ice and Winter are usually associated with Mathos. When those of Tiasis say "Mathos is coming" it means it is to be winter soon.

Obviously, Mathos' greatest strength is his ability to induce and strengthen winter. For three months or more, he will allow the land to slumber so it may rejuvenate.

Mathos is weak to fire as it can thaw him into a puddle of decimation.

None of the Old Pantheon answers to prayer, but it's said that if you carve a bear out of ice, Mathos will watch over you to aide you through the tougher times.

To pay homage to Mathos, you make a bear from his snow. The idea is that you help solidify his body, promising a swift winter that will result in a beautiful spring.

The holiday of Mathos is called Karmarsherrnus, named after the ritual done to bring him to form. It is celebrated from November 30th to the end of December 1st.

Another tradition is to help bears make their hibernation dens because the better the bears sleep, the stronger Mathos will be.

Mathos doesn't interact with the shire wolves, though there have been sightings of him.

Long ago, the land was hot and baked. The trees strained to bring life to the land even with the help of Menja and Taros. Radona gave them a brief rest but it was not enough for the trees.

They began to lose their leaves from exhaustion, losing their ability to take food from the sun and couldn't make it rain. They fell into a comatose state, many perishing.

Knowing that the future looked grim, the bears all came together to find a way to save the forests. They performed the Karmarsherrnus, a ritual of separating their souls from their bodies. Their bodies went into hibernation and Mathos was created.

When Mathos took form, the purely physical form of soul energy froze the land. The trees were frozen into a state of sleep, other animals also going to sleep to give more power to Mathos. When the three months were up, Mathos dispersed and spring came much greener and much more beautiful than before.

The trees left their comatose state, rejuvenated and more awake than ever before. The bears agreed that every year, they would hibernate so that the trees never become so strained as before and so every spring will be a time to rejoice.

All bears are the children of Mathos. A piece of him is inside of them all.

His life story is pretty much his 'main event'.

Mathos isn't my favourite but I like him a lot.