New Sejuani Skin - Bear Cavalry Sejuani

Are you ready to meet Bear Cavalry Sejuani?

For the on screen spoil, check this VOD and navigate to the 2:26:25 mark.

If you happen to read Russian, check out the Russian announcement here. It appears she will be like the other server celebration skins, meaning players on the Russian servers ( only ) should get her for free and all the other servers will be able to purchase her like a normal skin.

EDIT: Here's a translation of the Russian announcement:

"In the cold and frozen fields of Freljord even the most hardened warriors are held tested by nature's elements. Those with hopes to survive have to understand the very essence of nature's forces. The leader of the Winter's Claw and unmatched  boar rider, Sejuani, has learned to tame these forces like no other. But there comes a time when even the bravest of warriors have to call on the cavalry. And by cavalry we mean bears. Huge, angry, armoured bears. 

Riding on the back of a fierce beast, Bear Cavalry Sejuani will arrive soon to celebrate the launch of the Russian server. All summoners who play on that server will receive this skin for free in the very near future!"