The color represents Quantum, an undefined state that is triggered when you fill your combo counter with one certain color and then play another card of that very same color. This will cause your counter to overload and you will receive a black quantum spot.
This new mechanic will have a small effect on anyone who tries to play many cards of the same color, but more specifically it will allow you to play cards that have a black combo requirement from today onward. Not only will this allow us to create cards that require longer combochains in the future, it will also open up new tactics for anyones deck, because you can get a quantum state with any color you desire. Looking at our first three quantum cards, you can put these into all kinds of decks, so we hope you will enjoy experimenting until we release more cards of this kind.
Keep in mind that for this update you won't have to replace your HUDs in world. Also feel free to head over to our forums for some discussion on the topic!
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