Here's a summary of what we know so far about Kaldheim (We'll update this page as we discover more details from Wizards, so make sure to come back here if you want to find out the latest details).
Release Date & Other important dates
Tabletop Release: February 5, 2020
Launch Date: Feb. 6-7
Tabletop Prerelease: Jan. 29–Feb. 4
Magic Online & MTG Arena Release: Jan 28
Wizards noted that these dates represent the best information currently available, "but the situation is fluid". Back in October, Wizards in-store play suspension would be extended to January 2021, so I doubt that there will be official prerelease events for Kaldheim.
Storyline & Who Will Be Involved
The planeswalker Kaya visits a world of prophecy and legend, mortals and monsters. This will be the first Magic expansion to focus on the Norse mythology-inspired plane of Vikings. Wizards of the Coast also said that they will reveal the "next cast of characters as we adventure into Kaldheim and beyond" next week.
The first leak that revealed that Kaya is going to be a main character in the lore of Kaldheim came out last November.
Another character who might be featured in Kaldheim is Ramaz, the shamanic human planeswalker and crazed visionary who manipulated Chandra Nalaar into stealing the Dragon Scroll, which eventually led to the rise of the Eldrazi on Zendikar. He was first introduced in the 2014 Duels of the Planeswalkers game. Chandra tracked Ramaz across many planes to get revenge for using her in his schemes, but he ultimately escaped after their battle on the plane of Kaldheim. She learned that Ramaz's scheme traced back to the elderdragon Nicol Bolas.
Although Ramaz was introduced in Duels of the Planeswalkers, he was not featured in any Magic card in the game, so it's likely that we will see his first card featured in the Kaldheim set. If Ramaz shows up, will we see Chandra in the lore of the set as well?
So far, none of the leaks have confirmed if Ramaz will be featured, but it's likely that the set will introduce a new Planeswalker in Kaldheim.
Images of Wizkids' MTG miniatures also revealed the names of two gods who might be featured in Kaldheim: Alrund and Reidane.
Alrund, God of Wisdom
Reidane, Goddess of Justice
No further details about these new gods have been revealed yet, but we expect them to be based on the gods of Norse mythology. They will most likely be featured in cards just like the gods in the Greek mythology-inspired set, Theros.
Cards, Themes & Mechanics
Wizards of the Coast already confirmed that the four out of the ten Pathway Modal Double-Faced (MDFC) land cards will be released in Kaldheim. The six Pathway lands featured in Zendikar Rising will only get brand new art featuring the landscapes of Kaldheim in the upcoming Secret Lair: Ultimate Edition 2, but these cards will not be in the Kaldheim set.
Magic Head Designer Mark Rosewater also confirmed that the next two sets after Zendikar Rising (Kaldheim and Strixhaven), so Kaldheim will most likely feature more MDFC cards other than the four Pathway lands. All of the MDFCs in Zendikar Rising featured a land card in the back side, which is expected in a land-themed set, so Kaldheim's MDFCs will probably have a different card type in the back.
No mechanics have been revealed yet, but based on the art from the leaked packaging, the art from the 2009 Planechase set, and Duels of the Planeswalker game, we know that Kaldheim is a cold world of the Vikings, so we might see the return of Snow mechanics first introduced in the 1995 Ice Age set.
Two legendary creatures from the Kaldheim preconstructed Commander decks have already been revealed in the leaked packaging, and they are Larhril, Blade of the Elves and Ranar the Ever-Watchful.
Here are the incomplete details that the Redditors have seen from the leaked packaging:
Larhril, Blade of the Elves - 2BG
Based on colors of the Commander packaging, it looks like the Elves in Kaldheim will be Golgari-colored (Green and Black). The Blue/White Commander deck also hints that Spirits might be a common creature type in the Viking set.
Kaldheim Products and Other Packaging Images
Kaldheim Draft Booster Box
Kaldheim Collector Booster
Kaldheim Collector Booster Box
Kaldheim Set Booster Box