Plane setting: Valla. Setting of the card
Warstorm Surge 
and the Planechase card "Immersturm", this is a plane of total war. I have further developed this to have ties to old Nordic mythology (which it quite clearly has, but I am fleshing it out in this design).
I wanted to create a set where the
Warstorm Surge -ability is relevant, which is why I have made the
Unearth mechanic from the Shards block the returning mechanic. As will be demonstrated on one of the cards below, I also think that it fits very well both with the thought of a world constantly at war and with certain tenets in old Nordic mythological beliefs. Due to the flavor of the mechanic in this context, it will be centered in the colors
White and
Black with strands in
Red as well. I have not fleshed out the particulars of other mechanics in the set, but I imagine another mechanic revolving around combat to be found predominantly in
Red and
Green, and a third, non-combat mechanic centered in
Blue with a few cards in most or all other colors.
Taste of Vigor 
Instant (Common)
Put a +1/+1 counter on target creature and prevent all combat damage that would be dealt to that creature this turn.
"Eat of my fruit, warriors, and your youthful strength shall last forever." -Ydun, Goddess of the Golden Apples.
Comment: Nordic mythology (as many other mythologies of old) feature
golden apples. In nordic mythology, these provide the Asir, the "good gods", with everlasting youth.
Mechanically, this card shifts an ability traditionally found in White (targetted prevention) to Green, the color of general prevention (such as
Fog 
). I felt like this would be forgivable when coupled with a clearly green growth effect. The cost is not aggressive, but not vastly overcosted either (it is comparable to
Undying Evil 
) and I would imagine the card will see some limited play.
It also introduces the counter of this set as the +1/+1 counter.
Voelv's Weirding 
Sorcery (Common)
Look at the top two cards of your library. Put one of the cards into your hand and the other into your graveyard.
"The Voelv have ways to gaze into the distant future. Even kings would do well to heed their warnings."Comment: The word "Voelv" (same in plural) is one I've derived from the Danish "Vølv", a witch-like woman with the ability to "scry" to foresee future events. The process I have in mind here is simple and shamanistic, which is why I don't mind the "roughness" of this filter effect (putting the card in the graveyard). It also feeds the Unearthing theme of the set subtly (Blue doesn't have unearth in itself, though). This card is probably playable in limited as well as some constructed brews (compare:
Thought Scour 
).
Surt's Raiders 
Creature - Human Berserker (Uncommon)
Haste.
: ~ gets +1/+0 until end of turn.
When ~ enters the battlefield, add
to your mana pool.
"Beware those who follow Surt, the King of Flames. They are as ruthless and merciless as the wildest of fires."2/2
Comment: I chose to not put Unearth on my creature, instead tying it with the
Warstorm Surge -effect (which will check the power upon
resolution of its ability). The obvious thing to use the two last mana to do here is to pump the card itself. It can be an extremely overwhelming surprise later in the game, which is why it's obviously uncommon. Its body itself isn't too impressive in order to keep the power level a bit down (a 3/3 would probably be doable at rare, but...!). A good limited card but not something I would imagine fits into a lot (if any) constructed decks.
Oath of the Einharjr 
Enchantment (Rare)
Each creature in your graveyard has Unearth. The unearth cost is equal to its mana cost
(You may pay that creature's mana cost to return it to the battlefield any time you could cast a sorcery. If you do, it gains haste. Exile the creature at end of turn or if it would leave play).
"And from among the ranks of the fallen, the Valkyries will pick out the bravest of warriors and bring them to their next life in the army of the gods." -Voelv's prophecy.
Comment: The "All your relevant card types gain the set mechanic"-shtick is well-known and used by Wizards often. In Alara block, it was attached to
a Grixis-colored creature 
(I didn't know this when I designed this card although I had an inkling about it) which was mythic rare, and the cost was fixed at
. That, along with the body, made the Alara creature mythic. I feel like putting it at a cheaper enchantment in the new colors and make the cost fluid is enough justification to make this card and put it at rare.
Gungnir, Spear of Odin Legendary Artifact - Equipment (Mythic Rare)
Equip
Equipped creature has deathtouch and "
, unattach Gungnir, Spear of Odin: Destroy target creature, land, artifact or planeswalker".
The weapon of a god of death is a cruel thing to behold.Comment: Mythics have to (according to, among others, MaRo's latest article on Making Magic) be flashy without being overly complicated. This is it: The Spear of the Asir King, Odin, God of Death.
