Instant — Omen

Counter target spell with mana value 2 or less. (Then shuffle this card into its owner's library.)

Chilling Screech

Tarkir: Dragonstorm

Creature — Dragon

Flying
Whenever you cast a noncreature spell or a Dragon spell, this creature gets +2/+0 until end of turn.

Runescale Stormbrood

This is the actual decklist that I own.
Draft the Commanders first from a special pool (in the sideboard) with 4 packs of 10 or 12.
Each commander has partner. If you want to use one of the companions, you can do that as well if you abide by the companion rules and color identity rules. For Umori specifically, you may still have creatures as your commanders as long as the rest of the deck follows its companion rules.
I suggest choosing your commanders (and sometimes a companion) before you've drafted from the main pool. 
Each player automatically gets a command tower and an arcane signet.
Before drafting, players can decide if they want to draft 60 card commander decks or full-sized 100 card decks.
Draft 4 packs of 14 for 60 card decks and 6 or 7 packs of 14 for 100 card decks.
Color Identity does not matter when it comes to lands.
Draft Archetypes:
Reanimator
Cast spell, get value
Freecasting
Theft
Copying spells
Value for targeting your own creatures

(The Real) Budget Spellslinger Commander Cube

Storm

Draft Deck - Tarkir: Dragonstorm

Ur Dragon new

I realized that the main problem with the last iteration of this Cube was it included white. That pillar was taking a lot of space that could have gone to red and other colors. It seemed to dillute the experience so I made another one without such a useless color.
Special Rules:
Draft the Commanders 1st from a special pool (in the sideboard with 4 packs of 10 or 12)
Each commander has partner. If you want to use one of the companions, you can do that as well if you abide by the companion and color identity rules.
Each player automatically gets a command tower and an arcane signet.
Before drafting, players can decide if they want to draft 60 card commander decks or full-sized 100 card decks.

2nd Spellslinger Commander Budget Cube (Refocused)

Special Rules:
Draft the Commanders 1st from a special pool (in the sideboard)
Each commander has partner.
You may bypass the color identity restrictions if absolutely needed.
Each player automatically gets a command tower and an arcane signet.

Runescale Stormbrood

Rules Text

Card Facts

Legality

Rulings

Every version

Decks using this card