Color Matters

The main theme of Masa is color matters. The main theme should, of course, be reflected by the main mechanic. The main mechanic is:

Aspect

Aspect {mana} - If you have added {mana} or more to your mana pool this turn, {ability/effect}.

Some examples are:

Guardian of the Mist U

Creature - Human Wizard (R)

Aspect UU - If you have added UU ore more to your mana pool this turn, you may draw a card.

1/1

Guardian of the Leaves G

Creature - Elf Warrior (R)

Aspect GG - If you have added GG or more to your mana pool this turn, you may put a +1/+1 counter on Guardian of the Leaves.

1/1

"If you only spent {color} to cast ~, {effect}" is another small submechanic. I don't want TOO many of these as it might have a negative effect of making deckbuilding too linear. Thus, 3 cycles (1 at each rarity) with 1 at mythic, in my opinion, is enough to get the point across without being linear.

Original Fire 1R

Instant (UNC)

Original Fire deals 2 damage to target creature or player. If only red mana was spent to cast Original Fire, it deals 4 damage instead.

Original Sin 2B

Sorcery (UNC)

Return target creature card from your graveyard to your hand. If only black mana was spent to cast Original Sin, return target creature from your graveyard to the battlefield instead.

More to come as I think of them! I'm thinking this is a pretty good start, though.