What is time card?
No it's not what time you got into work. Conceptually these are support cards that have effect related to time/period i.e. TURNS in the game of Shadow Era.
Why not Artifact?
Technically these can be implemented as artifact; however, conceptually all of these card share the concept of its effect based on the global time i.e. turn numbers. Therefore, I have decided to call Environment - Time subtype as previously SpeakerOfTruth suggested Field card should indeed be called Artifact - Environment.
Why time card?
They have effect based on the timing of the game. So one obvious way is to give you benefit if you were to go second. Or use combination with Rain etc. to not only stall time but really take the timing as part of your strategy.
Assumptions
1. Just like Field cards, you can only have one time card in play at a time.
2. Assumed each players turn are counted cumulatively in global sense i.e. first player's first turn is TURN 1 but second player's first turn is TURN 2 etc.
Examples
1: Origin
Environment - Time
(1) Return all cards in your hand back into the deck and reshuffle. Draw cards that is one less than the cards that was in your hand.
Comment: This is essentially mulligan but if you think about doing mulligan any time you want, it is like in sense you are going back to the very beginning of the game i.e. Origin.
1: Shadow Era
Environment - Time
Every third turn, all Shadow allies in field increase 1 attack and 1 health. New shadow allies casted during these turns gain haste.
*Edited 4/13
Comment: This is just to illustrate the example that some huge effect can take place with these cards but only so often. Every third turn as follow: If you go first, at turn 3 i.e. your second turn you gain this. Next one happens turn 6 i.e. your opponent's third turn. 9th, which is your 5th turn.
1:Back to the future
Environment - Time
During the first three turn of yours, the first ally you cast gain 1 health. If it is even turn, the first friendly ally you cast costs one less.
Comment: This is one example (lame one) I can think of to be beneficial if you are going second. The even turn part basically make the latter ability only effective if you go second. But by decreasing casting cost, you are essentially negating the fact you are behind one resource when compared to the first player.
1:Jupiter time
Environment - Time
Every other turn at the beginning of your turn, the day and night changes. During the day, all shadow and rogue ally lose 1 attack. During the night, all shadow and rogue ally gain 1 attack.
Comment: Jupitar's day and night cycle is like half that of the earth. So essentially, I am trying to illustrate here that you now have rapid changes of day and night. During night, Shadow allies and Rogue do well but during day time not so good for them.
1:Slow motion
Environment - Time
Each player gain shadow energy and can only sacrifice every other turn.
Comment: I just can't think of good name referring to slow time cycle. But here essentially, any player can only build their resource pile half the speed i.e. the game becomes slower. The potential benefit of using this is for someone who wants to focus on the winny deck i.e. low costing creatures.
2:Time Shift
Item - Artifact
All time card effect will be shifted forward by one turn while Time shift is in play.
Comment: You can use this to screw up opponent's time card or perhaps use it well to get extra turn bonus. For instance, Origin's effect should take place in Turn 2, 4, 6 but if you shift by one it becomes 3 and 5 i.e. instead of your opponent's getting the bonus, you can now get his bonus. Another combo example is like with Shadow Era. You get third turn bonus with your Shadow Ally. So after your 3rd turn, your opponent's supposed get his bonus at turn 6 but if you use Time Shift at turn 5, instead of him getting at his turn 6, you get another at turn 7.
What do you think?